Towards increased strength and retained ductility of Zn–Mg-(Ag) materials for medical devices by adopting powder metallurgy processing routes

Towards increased strength and retained ductility of Zn–Mg-(Ag) materials for medical devices by adopting powder metallurgy processing routes Jiˇ rí Kub´ asek a,* , Selase Torkornoo b,** , David Neˇ cas a , Ingrid McCarroll b , Vojtˇ ech Hyb´ aˇ sek a , Baptiste Gault b,c , Eva Jablonsk´ a d , ˇ Crtomir Donik e , Irena Paulin e , Peter Gogola f , Martin Kusý f , Zdenˇ ek Míchal d , Jaroslav Fojt a , Miroslav ˇ Cavojský g , Jan Duchoˇ n h , Mark´ eta Jaroˇ sov´ a i , Jaroslav ˇ Capek a,h a University of Chemistry and Technology Prague, Faculty of Chemical Technology, Department of Metals and Corrosion Engineering, Technick´ a 5, 6 – Dejvice, 166 28, Praha, Czech Republic b Department of Microstructure Physics and Alloy Design, Max-Planck-Institut für Nachhaltige Materialien GmbH, Max-Planck-Straße 1, 40237, Düsseldorf, Germany c Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London, SW7 2AZ, UK d University of Chemistry and Technology Prague, Department of Biochemistry and Microbiology, Technick´ a 5, 6 – Dejvice, 166 28, Praha, Czech Republic e Institute of Metals and Technology, Lepi pot 11, SI-1000, Ljubljana, Slovenia f Slovak University of Technology in Bratislava, Faculty of Materials Science and Technology in Trnava, Ulica J´ ana Bottu 2781/25, 91724, Trnava, the Slovak Republic g Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Dúbravsk´ a cesta 9/6319, 845 13, Bratislava, the Slovak Republic h FZU – Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 8, Prague, 18200, Czech Republic i FZU – Institute of Physics of the Czech Academy of Sciences, Cukrovarnick´ a 112/10, 6, Prague, 16200, Czech Republic ARTICLE INFO Keywords: Zinc Bioabsorbable materials Mechanical alloying Spark plasma sintering Microstructure ABSTRACT The development of bioabsorbable zinc-based alloys with tailored mechanical properties and biocompatibility holds great promise for advancing medical implant technology. In this study, Zn–Mg and Zn–Mg–Ag alloys were synthesized using mechanical alloying (MA) followed by extrusion to achieve a combination of enhanced strength, ductility, and corrosion resistance. MA for 4 h produced ultrafine-grained powders incorporating Mg 2 Zn 11 intermetallic phases and oxide particles, which contributed to microstructure stabilization during subsequent processing. Extrusion consolidated these powders into dense materials with a uniform grain size of ~700 nm, exhibiting ultimate tensile strengths up to 435 MPa and elongation to fracture of ~12 %, representing a significant improvement over conventional processing methods. The addition of silver further enhanced the antibacterial properties, demonstrating notable efficacy against Staphylococcus epidermidis, while maintaining non-cytotoxic behavior in vitro. Corrosion rates remained low, with uniform surface degradation and the formation of protective corrosion layers. This work highlights the efficacy of combining powder metallurgy techniques to bioabsorbable zinc-based alloys with exceptional mechanical performance, corrosion behavior and in vitro cytocompatibility, providing a pathway for next-generation biodegradable medical devices. 1. Introduction Zn–Mg alloys are considered perspective materials for applications in biodegradable stents or for bone fixations, especially in maxillofacial surgery, due to their reasonable corrosion rate and excellent biocompatibility [1–3]. Their function is supposed to be time-limited with complete replacement by newly healed tissue [2,4], which helps to prevent long-term issues with inflammations leading, in some cases, even to the removal of the implant as observed in other systems including Mg-based or Fe-based biodegradable materials. Localized corrosion leads to the premature loss of mechanical integrity and hydrogen gas (H 2 ) release casts doubts on the usability of Mg-based materials [2,4]. Fe-based materials degrade by forming iron oxides/hydroxides, which are not sufficiently soluble in the organism and may cause serious health issues [2,5]. Zinc and its alloys, on the contrary, dissolve slowly in an organism, and the corrosion reactions do not * Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (J. Kub´ asek), [email protected] (S. Torkornoo). Contents lists available at ScienceDirect Journal of Materials Research and Technology journal homepage: www.elsevier.com/locate/jmrt https://doi.org/10.1016/j.jmrt.2025.06.185 Received 10 April 2025; Received in revised form 23 June 2025; Accepted 24 June 2025 Journal of Materials Research and Technology 37 (2025) 4345–4361 Available online 8 July 2025 2238-7854/© 2025 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ). form harmful by-products in the human body (no H-release, biocompatible corrosion products) [3,5]. Expanding the use of Zn as a bioabsorbable material requires improvements in mechanical properties, which can be achieved through alloying with suitable elements, including Ag, Cu, Li, Mg, Mn. Among them, Mg seems to be the best candidate for improving the material’s strength, decreasing the modulus of elasticity [1], and positively affecting bone mineralization and overall biocompatibility [6]. The maximum solubility of Mg in the Zn matrix is near 0.3 at.% at 364 ◦C and decreases to almost zero at ambient temperature [2,7], leading to the precipitation of intermetallic phases [8]. These include Mg 2 Zn 11 , MgZn 2 , Mg 7 Zn 3 , Mg 2 Zn 3 and MgZn, which are hard and brittle, thereby improving strength but decreasing ductility. Zn–Mg materials however generally exhibit a low biodegradation rate. Further improvement of the mechanical properties can be achieved through mechanical alloying (MA). MA causes an intensive plastic deformation during the process, which leads to the formation of alloy powders containing metastable phases. These include oversaturated solid solutions with extremely small particles and grains, reaching nanograined materials [9]. However, MA is highly dependent on the processing conditions, including the milling media and vessels, their shape and size, temperature and atmosphere during processing, and also additional control agents, such as stearic acid, which are added to prevent excessive cold welding [9,10]. Although MA technology is capable of preparing ultrafine-grained materials, the preserving of such microstructure during the consolidation at increased temperatures (>200 ◦C) is challenging due to the low recrystallization temperature of pure zinc (<0 ◦C) [11], resulting in the materials’ recrystallization and coarsening, especially when the milled powder is highly stressed. Cold isostatic pressing (CIP) and conventional sintering of green compacts [12,13], hot isostatic pressing (HIP) [13], spark plasma sintering (SPS) [13] and extrusion (E) [13,14] are generally considered for Zn-based alloys compaction. The resulting materials possess microstructures with extensive porosity, oxides and inhomogeneities in chemical and phase composition, significantly deteriorating mechanical properties. Classical sintering at an increased temperature usually takes several hours before sufficient compaction takes place, resulting in coarse-grained microstructures. A similar problem occurs during hot isostatic pressing, where materials are exposed to high temperatures for several hours, affecting the microstructure or phase composition [15–17]. The materials’ recrystallization and coarsening, may be, to some extent, prevented using compaction by spark plasma sintering (SPS). SPS offers the advantage of a fast compaction technique with short times and low temperatures of the process (0.7 of the melting temperature of the metal to be compacted) [17,18]. In this technique, pulses of electric current flow through the sample and generate heat at the powder particle interfaces due to the local high resistance. Besides, the process is accompanied by adjustable compression and can produce materials with a homogeneous nonporous structure without significant grain coarsening [18–20]. Zn-alloys have also been prepared by additive manufacturing methods such as laser powder bed fusion (LPBF) [21–23]. However, based on the alloy composition, the density of the prepared materials reached a maximum of 98 %. Furthermore, the eutectic microstructure was formed along grain boundaries, and at higher magnesium concentrations (>7.7 at.%), the inhomogeneous microstructure was generated due to local precipitation of the MgZn 2 phase. Those issues negatively affect mechanical properties [21]. Here, we prepared materials by combining MA, SPS and extrusion, to develop a fine-grained microstructure in Zn-based alloys. As a starting material, we have selected Zn-2.6Mg (at.%) corresponding to the Zn–1Mg in wt.%, which repeatedly showed, after a conventional way of production, a good compromise between strength and ductility [3,24]. Due to the uniqueness of the materials preparation route, a main emphasis was placed on the study of the microstructure, which has subsequently serious impact on both mechanical and corrosion properties. To provide morphological, crystallographic and compositional information from millimeters to nanometers, we combined scanning-electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT). In particular, APT provides detailed information about the material’s nanoscale composition in 3D, though serving as a very helpful complementary technique for conventional 2D imaging techniques such as electron microscopy. Furthermore, we investigated how the addition of Ag affects the microstructure, mechanical performance and dissolution of the material. Here, we discuss the details of the microstructure-property relationships in these alloys and demonstrate their high potential for direct application as bioabsorbable metals. 2. Materials and methods 2.1. Materials synthesis The Zn-2.6Mg and Zn-2.6Mg-0.6Ag alloys were prepared by mechanical alloying (MA) for 4 h using 800 rotation per minute (RPM) in a Retch E-max mill equipped with a water-cooling system capable of maintaining a temperature below 50 ◦C. The powders used were pure Zn (99.9 %, particle size <149 μ m, Alfa Aesar), Mg (99.8 %, particle size <44 μ m, Alfa Aesar) and silver (99.9 %, particle size <20 μ m, Safina a. s.). The ball-to-powder ratio (B/P ratio) was selected as 5:1. The grinding process was carried out using zirconia balls in a 125 ml elliptically designed vessel with zirconia coating. To prevent powder agglomeration during the mechanical alloying, 0.03g stearic acid was added to the powder mixture before milling. Materials were mechanically alloyed under a protective Ar atmosphere (99.96 %). The MA parameters were selected based on several experiments documenting the effect of various parameters on powder properties. Two methods of compaction of alloyed powders were selected. Firstly, the fast compaction method – spark plasma sintering (SPS - FCT Systeme HP-D 10) was performed at 300 ◦C, 80 MPa pressure for 10 min in graphite tools under a protective Ar atmosphere (99.96 %). Secondly, the Zn–2.6Mg alloy was compacted by hot extrusion at 200 ◦C with an extrusion ratio (ER) equal to 25. Before extrusion, “green compact” from powders were produced in the form of cylinders with 30 mm in diameter and 50 mm high by vacuum hot pressing (HVP) at 200 ◦C for 2 h. The designation of the synthesized materials is shown in Table 1. The chemical composition of the prepared powders and compacted materials was verified by atomic absorption spectrometry - AAS (Agilent 280 FS AA spectrometer). 2.2. Microstructure The prepared samples were first ground on SiC papers P400 – P2500, then polished on diamond paste D2 (UR-Diamant), and finally polished on the Eposile NonDry suspension (QATM) for 20 min. The microstructure was characterized using an SEM (TESCAN VEGA 3 LMU) with an EDS analyzer (OXFORD Instruments AZtec). Additionally, electron Table 1 The materials designation and processing conditions. Materials designation Alloy composition [at. %] Alloy composition [wt. %] Mechanical alloying Compaction method and conditions Zn2.6Mg (4h) Zn-2.6Mg Zn–1Mg 800RPM, 4h, BP =5:1 – Zn-2.6Mg0.6Ag (4h) Zn-2.6Mg0.6Ag Zn–1Mg–1Ag 800RPM, 4h, BP =5:1 – Zn2.6Mg (4h) +Ex Zn-2.6Mg Zn–1Mg 800RPM, 4 h, BP =5:1 Extrusion, 200 ◦C, ER25 Zn-2.6Mg0.6Ag (4h) +Ex Zn-2.6Mg0.6Ag Zn–1Mg–1Ag 800RPM, 4 h Extrusion, 200 ◦C, ER25 J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4346 backscattered diffraction (EBSD) analyses were performed on an Apreo 2 SEM using an acceleration voltage of 15 kV with a probe current of 13 nA after final polishing was performed using OPS for 20 min. EBSD Kikuchi patterns were measured with a Symmetry S3 camera (Oxford instruments) using AZtec software. Samples were tilted 70◦for measurements and an acceleration voltage of 15 kV of used. The data were processed using AZtecCrystal software. Observation and documentation of the microstructure at a nanoscale was performed using a FEI Tecnai TF20 X-twin field emission gun transmission electron microscope (TEM) operated at 200 kV and equipped with an EDS detector. Particularly, scanning transmission electron microscopy (STEM) mode was used for the microstructure observation. For STEM, Z-contrast imaging was performed using a high-angle annular dark field (STEM–HAADF) detector. Samples for TEM analyses were prepared using a JEOL ION SLICER EM 09100 IS with a voltage of 5 kV and a current of 120 μ A. The phase composition was measured by X-ray diffraction (X’Pert 3 Powder instrument in Bragg-Brentan geometry using a Cu anode (λ =1.5418, U =40 kV, I =30 mA). Quantitative phase analysis was carried out using the whole pattern Rietveld refinement software MAUD [25]. The theoretical porosity was calculated from the prepared samples’ weight, volume, and density. Image analyses in ImageJ software measured the grain size. A 2.5 μ m ×20 μ m region of the polished sample was coated with 1 μ m of platinum carbon (Pt–C) using a gas-injection system inside a dualbeam scanning electron microscope/focused ion beam (SEM/Ga FIB) (FEI Helios Nano-Lab 600i) (FEI Company, Hillsboro, OR, USA) at 3.0 kV and 1.4 nA. A trench was milled using a voltage of 30 kV and a current of 2.5 nA on each side of the Pt–C-coated lamella. Next, 3 μ m ×3 μ m of the lamella edge was milled at 30 kV and 0.23 nA to attach the 2.5 μ m ×20 μ m lamella to the OmniProbe 200 Nanomanipulator (Oxford Instruments, Abingdon, UK) with Pt–C. Lamella (2.5 μ m ×2 μ m) were mounted onto Presharpened Microtip™ Coupons (PSM M36) (CAMECA Instruments, Madison, WI, USA) and sharpened into needle-like shapes with a diameter of 30–100 nm. The Zn–1Mg (4h) +Ex sample was analyzed in the LEAP™ 5000 XR (CAMECA Instruments, Madison, WI, USA using a laser pulse energy of 50 pJ, a base temperature of 50 K, and a repetition rate of 125 kHz, and the detection rate was fixed at 5 ions detected per 1000 pulses on average. The Zn–1Mg (8h) +Ex sample was analyzed in the LEAP™ 5000 XR (CAMECA Instruments, Madison, WI, USA using a pulse fraction of 20 %, a base temperature of 50 K, and a repetition rate of 200 kHz, and the detection rate was fixed at 5 ions detected per 1000 pulses on average. The Zn–1Mg–1Ag (4h) +Ex sample was analyzed in the LEAP™ 5000 XS (CAMECA Instruments, Madison, WI, USA using a pulse fraction of 20 %, a base temperature of 50 K, and a repetition rate of 500 kHz, and the detection rate was fixed at 5 ions detected per 1000 pulses on average. The reconstruction of all datasets and analysis were performed in CAMECA Instruments APSUITE (version 6.3.0.90). 2.3. Mechanical properties The mechanical properties of the prepared alloys were characterized by Vickers hardness and tensile tests. HV1 was measured on a FutureTech FM-100 at a load of 1 kg for 10 s. Tensile tests were performed using an Instron 8802 instrument on “dog bone” specimens (Fig. S1 – supplementary file), respectively, at a strain rate of 0.003 s −1 . 2.4. Corrosion behaviour To describe the corrosion properties of the material, a 7-day exposure was performed, extended by non-destructive electrochemical measurements: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and polarization resistance (R P ). Measurement was performed in a complex body simulation, i.e. in EMEM M7278 with 5 % FBS (Foetal Bovine Serum, Sigma Aldrich) and the necessary addition of 1 % antibiotics/antimycotics (all Sigma Aldrich) at 37 ◦C. Cylindrical samples 10 mm high and 4.3 mm in diameter were ground (to FEPA P2500), washed with demi-water and degreased in ethanol. Samples were further, mounted on a PTFE (Polytetrafluoroethylene) holder immediately before measurement. Subsequently, the samples, together with glassy carbon rods and a 75 ml polymethylpentene cell, were sterilized using UV-C (ultraviolet light in the wavelength range of 100–280 nm (nm). Afterwards, the measuring cell was assembled and an ethanol-washed silver-chloride reference electrode (SSCE - Silver/Silver Chloride Electrode, 3 mol/KCl) was added. During the subsequent exposure, OCP was acquired, intermittently by R P measurement (+-15 mV/OCP, 0.125 mV/s) or EIS (60 kHz −0.01 Hz, 7 points per decade, E AC 15 mV.rms, E DC =OCP). Measurements were performed on a Gamry Reference 600 potentiostat, the correctness of the impedance data was verified by Kramers-Kronig transformation in Gamry Echem Analyst software, and subsequent evaluation was performed in ZView software. The material was also analyzed after exposure using SEM/EDS Tescan Vega 3 and OXFORD Instruments AZtec and a light microscope Olympus SZX10 (LM). 2.5. In vitro biological behavior 2.5.1. In vitro cytotoxicity test - test on extracts Human foetal osteoblasts hFOB 1.19 (ATCC® CRL-11372™) were maintained in DMEM/Ham’s F-12 (Sigma, D6434) medium with 10 % FBS (Foetal bovine serum - Sigma F7524), 2.5 mM L-glutamine in the form of stable dipeptide (Sigma, 8541) and selection reagent G418 (Sigma, G8168) at a permissive temperature of 34 ◦C, with 5 % CO 2 and 100 % relative humidity. Cells were passaged regularly using a trypsinEDTA solution without phenol red (Gibco, 15400054). Cells were used from the 3rd passage after thawing and only until the 15th passage. On day 1, hFOB 1.19 cells were trypsinized and resuspended in the cultivation medium to obtain a suspension with a concentration of 2⋅10 5 cells per mL. Subsequently, 100 μ l of the cell suspension was seeded in a 96-well plate, which means the seeding density of 2⋅10 4 cells per well. Cylindrical samples (height 10 mm, diameter 4 mm) of the alloys (Zn-2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) +Ex ) were weighed, sterilized by 70 % ethanol (2 h) and by UV light (2 h). Thereafter, samples were transferred to a cultivation medium L-15 (Leibovitz’s L-15 medium) supplemented with reduced concentration of FBS (5 %, as suggested by ISO 10993-5 standard) without G418 and agitated (130 RPM) at 37 ◦C in closed vessels for 24 h. The surface-to-volume ratio stated in the ISO 10993-12 (1.25 cm 2 mL −1 ) was adjusted as recommended for degradable metals [26] i.e. the volume was five times higher. Three replicates were used for the alloys tested. On day two, the medium in 96-well plates was replaced by the extracts prepared as described above. The extracts were used undiluted (100 % extracts) and twice diluted (50 % extracts). Six technical replicates were used for each sample. Sole cultivation medium L-15 served as negative (unaffected) control. The concentration of released ions in the extracts was measured by AAS. On day three, after 24 ±1 h of incubation with the extracts at 37 ◦C without CO 2 , the cell metabolic activity was evaluated by a resazurin assay. Resazurin is metabolized to resorufin by living cells. The extracts were removed and a resazurin solution (final concentration 25 μ g mL −1 ) in Hank’s balanced salt solution (HBSS) was added. After 2 h, fluorescence at 560/590 nm (excitation/emission) was measured (Fluoroskan Ascent FL, Thermo). Cytotoxicity of the extracts was calculated as a percentage of the metabolic activity of the negative control. Extracts causing a decrease below 70 % of the activity of the negative control were considered cytotoxic, as described in the ISO 10993-5 standard. 2.5.2. Antibacterial tests Antibacterial tests were performed with Escherichia coli (DBM 3138) as a representative of Gram-negative bacteria and Staphylococcus epidermidis (ATCC14998 CCM21245) representing Gram-positive bacteria. The test conditions were adopted from Ref. [27]. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4347 A bacterial suspension was prepared the day before the test. The bacteria were inoculated into the liquid Luria-Bertani (LB) medium (Lennox) and incubated at 37 ◦C overnight. On the day of the experiment, the bacterial suspension was diluted with phosphate-buffered saline (PBS) to a turbidity of 1 McFarland standard (which corresponds to approx. 3⋅10 8 colony forming units, CFU/mL for E. coli). Subsequently, a serial dilution was prepared; the sixth decimal and fourth decimal dilutions were used for E. coli and S. epidermidis, respectively. The specimens Zn-2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) + Ex (height 3 mm, diameter 4 mm) were sterilized in 70 % ethanol (2 h) and under UV light (2 h) and then submerged in 0.5 ml of bacterial suspension (the surface to volume ratio was 1.25 cm 2 per mL). The samples were incubated in bacterial suspensions for 4 h at laboratory temperature. Three replicates were used for each type of material. Copper was used as a positive (antibacterial) control. The negative control (suspension without samples) was used as a control of bacterial growth. After 4 h, the drip test was performed by transferring 25 μ L of suspension into each field of Petri dish (LB agar for E. coli and plate count agar, PCA for S. epidermidis) divided into twelve squares. A Petri dish contained four drops (of 25 μ L) of each triplicate of one specimen. Thus, every type of sample was applied on one plate. Blank (pure PBS) and a control dish (bacterial suspension without samples) were prepared using the same drip method. Furthermore, a subsequent 1:1 dilution of each suspension was performed with PBS to ensure the countability of the colonies in the case of too large number of colonies in the original suspensions. The plates were then left at laboratory temperature and, if necessary, the next day transferred to 37 ◦C until the colonies on the control plate were visible and suitable for counting. Colonies on plates were counted using the Schuett Count device. The colonies counts were compared to the count in the control dish. Furthermore, the same set of samples was sterilized and incubated for 4 h in the same volume of PBS as for the antibacterial test. The concentration of released Zn was measured by AAS. 3. Results 3.1. Microstructure 3.1.1. Processing of powders by mechanical alloying Electron micrographs of the supplied powders are displayed in Fig. S2 (supplementary file). These powders were combined in appropriate volumes in the milling vessels to produce mechanically alloyed powders. Firstly, we have studied the effect of long-term high-energy MA on the microstructure development of the Zn-2.6Mg alloy, including phase and chemical composition. Both MA powders were very fine, without agglomerates, due to controlled milling parameters and the addition of stearic acid (Fig. 1). The powder particles were further characterized by sharp edges and a layered structure, which is caused by the repeated cold welding of the input particles and their subsequent breakage. The individual particles were up to 90 μ m in size; however, the main fraction was 30 ±17 μ m for Zn-2.6Mg (4h) and 24 ±12 μ m for Zn-2.6Mg0.6Ag (4h) . The final size of the alloy powders is reduced compared to the input zinc powder. We expect that this is affected by two main factors. Firstly, prolonged exposure to temperature-controlled MA crushes the powder by the impact of the grinding balls. Secondly, due to the low magnesium solubility in zinc, it is likely that brittle intermetallic phases precipitate during the milling and support the disintegration of larger particles. Such behavior is supported by the identification of the Mg 2 Zn 11 phase in the milled powder by X-ray diffraction (Table 2 and Fig. 4). Furthermore, the XRD results of MA powders (Table 2, Fig. 2) revealed no MgZn 2 although metastable conditions could lead to its formation. Our previous work has shown that mechanical alloying at 800 RPM leads to the formation of alloy in a shorter time (4 h) than at lower RPM values [28]. Increasing the milling time to 8 h led even to the dissolution of almost all the input magnesium in the Zn matrix. Subsequent AAS analyses of the MA powders confirmed that the composition is as designed, proving there were no selective losses of Mg in the milling vessels during the process. 3.1.2. Consolidated materials Fig. 3 shows the phase composition of compacted Zn–Mg-(Ag) materials with the evaluated results reported in Table 2. The compacted Zn2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) +Ex materials exhibited comparable phase composition as the powder precursors. The slight increase in the content of Mg 2 Zn 11 in the extruded products can be attributed to the further precipitation of Mg 2 Zn 11 during the consolidation process. Besides, traces of MgO were observed by detailed analyses in similar amounts in powder precursors and compacted materials indicating some preferential oxidation of Mg. It is worth mentioning that MgO diffraction Fig. 1. Mechanically alloyed powders: A) Zn-2.6Mg (4h) B) Zn-2.6Mg-0.6Ag (4h) . Table 2 The phase composition of prepared MA powders and compacted products according to XRD. Material conditions Phase composition [wt.%] Zn Mg 2 Zn 11 Ag 0.12 Zn 0.88 MgO Zn-2.6Mg (4h) Powder 93.0 6.2 –0.8 Zn-2.6Mg (8h) Powder 99.3 – – 0.7 Zn-2.6Mg-0.6Ag (4h) Powder 92.8 6.4 <0.1 0.7 Zn-2.6Mg (4h) +Ex Compact 91.9 6.9 –1.2 Zn-2.6Mg-0.6Ag (4h) +Ex Compact 92.2 7.0 <0.1 0.8 J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4348 peaks partially overlap with the Mg 2 Zn 11 phase at 36.9 and 42.9 ◦2θ positions, making them difficult to observe in XRD patterns. ZnO was not detected, although its presence under the detection limit cannot be excluded. It is worth mentioning that the alloy milled for 8 h suffered from extensive cracking during extrusion. This happened even with the processing temperature up to 400 ◦C. Therefore, Zn-2.6 Mg (8h) +Ex is not further studied in the paper. 3.1.2.1. Microstructure analyses using SEM with EDS and EBSD. As shown in the scanning electron micrographs in Fig. 4., both successfully synthesized (Zn-2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) +Ex ) materials prepared by extrusion have an ultrafine-grained microstructure with a typical arrangement of intermediate phases in the rows parallel to the extrusion direction (Fig. 4a–d). Further figures of microstructure are shown in Fig. S3 – supplementary file. Firstly, the microstructure of both materials contained phases enriched by Mg with a size in the range of 0.3–1 μ m (Fig. 4b and d). These phases were analyzed using SEM-EDS and contained about 14.6 at. % of Mg, which corresponds to the Mg 2 Zn 11 phase. Due to the size of these phases, their arrangement and confirmation of their presence in the powder precursor by XRD (Table 2), it is believed that they were formed during mechanical alloying. Indeed, the estimated content of Mg 2 Zn 11 in Zn–1Mg (4h) using Rietveld analyses of XRD was 15.1 at.%. Simple recalculation shows us that it corresponds to the 2.5 at.% of Mg in the alloy, indicating that Mg would be dissolved in the matrix in a very low concentration (≈0.1 at. %), further confirming that these phases are not formed during extrusion. Other smaller phases were observed in the microstructure mainly at the grain boundaries. Due to the existence of oxide shells on the surface of powder particles breaking during MA, these phases are expected to be oxide particles incorporated inside the microstructure during extrusion. This will be further discussed below. The in-plane inverse pole figure (IPF) maps (Fig. 5) obtained by EBSD reveal the grain size and orientation. Both materials have comparable grain size distribution (Fig. 6) with the average grain size of 0.74 and 0.72 μ m for Zn-2.6Mg and Zn-2.6Mg-0.6Ag, respectively. Both materials have very low texture strength with signs of (0110)and (1210)fiber texture (Fig. 7) and with the preferential orientation of basal planes parallel to the extrusion direction. However, the texture is much weaker compared to the Zn-based alloys prepared by conventional casting and wrought techniques (eg. hot extrusion, rolling, ECAP) [2,29,30]. Both, the presence of ultra-fine grains and more random distribution of crystallographic orientations are believed to be affected by the presence of intermediate phases in the size from tenths to hundreds of μ m. To confirm this assumption further detailed analyses of the microstructure using APT and TEM were performed. 3.1.2.2. Detailed microstructure analyses using APT and TEM. The results of the APT analyses on the extruded materials are shown in Fig. 8 and Table 3. The Zn–1Mg (4h) +Ex sample contains mainly the Zn matrix and finely dispersed but unevenly distributed particles (Fig. 8a). The composition (at. %) of the different phases was obtained using profiles along a 5x5x4 nm cylinder with a bin size of 0.3 nm. Subsurface intermetallic particles show a Zn/Mg ratio consistent with the Mg 2 Zn 11 phase as reported in Table 3. Precipitate I (Fig. 8b), which intersects the specimen’s surface is enriched in oxygen, mostly in the form of ZnO/Zn (OH) 2 ions in the APT analysis. Due to surface contamination during sample preparation and the presence of residual gas in the APT analysis chamber, accurate quantification of O and H is a known challenge and contributes to the variation of O and H on the surface layer [31–33]. Yet, this enrichment compared to the Zn phase, can be considered as indicative of preferential oxidation. The second intermetallic phase containing mostly Zn and Mg has Zn/Mg ratio inconsistent with equilibrium phases known in the Zn–Mg system and probably corresponds to the presence of an intermediate metastable phase. Fig. 8c is a composition profile using a 10x10x10 nm cylinder and a bin size of 0.3 nm showing a clear increase in Mg composition. These could be the formation of Guinier-Preston (GP) zones or clusters precursor to the intermetallic phase. The results of APT analysis of the Zn-2.6Mg-0.6Ag (4h) +Ex shown in Fig. 8d indicate the presence of a Zn phase and an intermetallic phase with tenths of nm in size. The bulk composition (at%) of the phases was obtained by an analysis of a 5x5x4 nm cylinder and a 10x10x4 nm cylinder. The intermetallic phase corresponding to precipitate I-III (Fig. 8d) contains mostly Zn and Ag. Precipitate III has a composition consistent with the Ag 0.12 Zn 0.88 ε -phase. No Ag-containing intermetallic phase was observed using XRD for the milled powder, whereas the presence of the ε -phase was confirmed by XRD in the extruded material indicating the precipitation of these phases during the extrusion. Fig. 8e and Fig. f, respectively suggest that grain boundaries and dislocations (Fig. S4 - supplementary file) are attractive segregation sites for Ag. The grain boundaries enriched with Ag are also decorated by clusters of Mg. The pattern formed by the assembly of Ag-segregated dislocations can be interpreted as a low-angle boundary as revealed by APT in other alloy systems [34–36]. TEM-EDS analyses of the Zn-2.6Mg (4h) +Ex revealed that nano-sized particles both at grain boundaries and inside the grains correspond to the Mg 2 Zn 11 and/or magnesium or zinc-enriched oxides (Fig. 9). These particles are smaller than the thickness of the lamellae, therefore the values of chemical composition estimated by EDS are affected by the surrounding matrix. For this reason, it is difficult to exactly distinguish oxide particles and the Mg 2 Zn 11 phase with oxidized surface as suggested by several APT observations. We believe that part of these particles come from the breakage of the oxide shells (ZnO) located at the surface of the powder precursors. This can be potentially the main source of observed ZnO inside the consolidated materials. XRD analyses of MA powder precursors (Table 2) also revealed the presence of MgO. This thermodynamically stable phase is preserved also in the consolidated materials. Mg 2 Zn 11 was also observed in the MA powder precursors, however, its content is slightly increased (Table 2) for Fig. 2. XRD patterns of the Zn-2.6Mg-(0.6Ag) powders prepared by MA. Fig. 3. XRD patterns of the Zn-2.6Mg-(0.6Ag) extruded materials. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4349 consolidated materials. This may indicate the in-situ precipitation of this phase during the extrusion process. These results are supported by almost the extremely low amount of Mg dissolved in the zinc matrix measured by APT (Table 3). We were not able to distinguish between the oxides and intermetallic particles reliably, because of the image artefacts, low contrast difference and similar shape and size. In general, the secondary phases form particles of a size ranging between approximately 10 and 30 nm. The TEM analyses also revealed the Zn-based matrix contained large number of finer grains/subgrains with a size ranging between approximately 50 and 150 nm. The particles and precipitates help pin grain boundaries and, therefore, prevent microstructure coarsening. Although the temperature of the preconsolidation and extrusion process was relatively high (200 ◦C), the presence of these particles is believed to be the main reason for the low average grain size (below 1 μ m) in the extruded products. 3.2. Mechanical properties The mechanical properties of the studied materials were evaluated based on tensile tests. The true stress-strain curves are plotted in Fig. 10a. Due to the similarities of measurements and for clarification, only one measurement from three is shown. Results considering average Fig. 4. Microstructure of the consolidated materials - SEM: a), b) Zn-2.6Mg (4h) +Ex ; c), d) Zn-2.6Mg-0.6Ag (4h) +Ex ; red arrows indicate Mg 2 Zn 11 phase, blue regions indicate the oxide particles pinning the grain boundaries. Fig. 5. IPF maps of the compacted materials: a) Zn-2.6Mg (4h) +Ex , b) Zn-2.6Mg-0.6Ag (4h) +Ex , extrusion direction is the reference direction of map. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4350 values and standard deviations are summarized in Fig. 10b and also supplementary data (Table S1 – supplementary file). Results for an extruded Zn-2.1Mg-1.15Sr alloy are added for comparison as an example of a widely studied alloy, with properties fulfilling requirements for integration in medical devices. This material was prepared by a common top-to-bottom approach (melting, homogenization annealing and hot extrusion), resulting in Zn mean grain size of approximately 2.5 μ m [37,38]. Zn has a low melting temperature (420 ◦C), making 37 ◦C rather high homologous temperature for testing. To show the effect of temperature on mechanical properties, tensile tests at 37 ◦C have been performed for Zn-2.6Mg (4h) +Ex and also Zn-2.1Mg-0.15Sr Ex as a reference alloy. Due to the limited quantity of material available following the preparation process, it was not possible to conduct tensile mechanical property measurements at 37 ◦C for the Zn-2.6Mg-0.6Ag (4h)+Ex alloy. The values of TYS (279 MPa) and UTS (384 MPa) for the Zn-2.6Mg (4h) +Ex exceed the performance of a majority of binary Zn–Mg or more complex alloys produced by conventional techniques like casting, extrusion, rolling [3]. Furthermore, the Zn-2.6Mg-0.6Ag (4h) +Ex alloy reached an 11 % higher value of TYS and 13 % higher value of UTS at almost similar elongation to fracture (E). Both Zn-2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) +Ex showcase a significant increase in strength at the expense of their ductility. Minor deviations were observed among measurements for TYS, and UTS, although the ductility of Zn-2.6Mg-(0.6Ag) (4h) +Ex fluctuated more, suggesting that the microstructure of the prepared alloys was slightly heterogeneous and the secondary phases were locally concentrated, causing the increase in local internal stresses and decreased ductility. It is evident from Table 2 and Fig. 10 that all Zn-based materials tested at 37 ◦C instead of laboratory temperature lose in mechanical performance significantly. The TYS and UTS values for Zn-2.1Mg0.15Sr Ex representing the reference material are decreased to 222 and 276 MPa which is even below the suggested tolerable values, while due to the generally higher mechanical strength of Zn–1Mg, the measured values of TYS and UTS at 37 ◦C correspond to the 246 MPa and 329 MPa, respectively. In summary, the decrease in mechanical strength is in both cases ≈14 %. Comparing the shapes of the individual tensile curves (Fig. 10a), one can see that the curves of all powder metallurgical materials are of the same shape. Further data evaluation considering the true stress – true strain values are shown in Fig. S5 – supplementary file. Obtained results suggest that the deformation is accommodated by the same deformation mechanisms independent on the chemical composition and testing temperature. The reference alloy shows a significant increase in ductility after the increase in the testing temperature, while maintaining the general shape of the curve. To obtain more information, we treated the curves according to Ref. [39] and evaluated strain hardening coefficient n, strain hardening rate and dislocation storage density (Eqs. (1) and (2)). σ =K⋅ ε n(1) θ=d σ d ε (2) In these equations σ is normalized plastic true stress, ε is normalized plastic true strain, n is strain hardening coefficient, K is strength constant and θ hardening rate. The dislocation storage rate was evaluated as the slope of linear part of the hardening rate*normalized plastic stress vs. normalized plastic stress curves [39]. The plots showing various dependencies of mechanical behavior are shown in Fig. S4 (supplementary file) and the important values evaluated from those curves are listed in Table 4. It is important to note that strengthening part of the curves belonging to powder metallurgical samples was very short and it was very difficult to distinguish the elasto-plastic and plastic deformation region, which could lead to the overestimation of the value of strain hardening coefficient. Fig. 6. The distribution of grain size: a) Zn-2.6Mg (4h) +Ex , b) Zn-2.6Mg0.6Ag (4h) +Ex . Fig. 7. The texture of studied materials presented by IPFs: a) Zn-2.6Mg (4h) +Ex , b) Zn-2.6Mg-0.6Ag (4h) +Ex . J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4351 3.3. Corrosion The corrosion behavior of the Zn-2.6Mg (4h) +Ex and Zn-2.6Mg0.6Ag (4h) +Ex was studied by performing a one-week exposure in an EMEM - medium simulating blood plasma, both in terms of similar inorganic ion content and biochemical component presence. After exposure, the materials were analyzed by SEM/EDS, then mechanical removal of bulk corrosion products was performed, and materials surface again analyzed by SEM/EDS (Fig. 11) and by OM (Fig. S6 – supplementary file). From an overall perspective, there is a noticeable difference between the materials. The Zn-2.6Mg (4h) +Ex alloy shows significantly fewer changes compared to the original surface, the main ones being long fibrous deposits occupying a small part of the surface. Their shape indicates their protein origin. Zn-2.6Mg (4h) +Ex surface has observable furrows after grinding of the material. Their slightly blurred contours, together with the change in color of the material to blue-grey, indicate the presence of a thin film. According to the EDS, the thin film composition can be estimated to be predominantly a mixture of oxide and carbonate. Looking at the less abundant elements, apart from Mg with a lower abundance than in the bulk, the presence of calcium and phosphorus in approximately equiatomic proportions can be observed. Long fibrous deposits are also visible and their shape indicates their protein origin. After mechanical removal of the deposits, a localized attack site is observed with numerous small sharp-edged crevices and a larger central pit containing corrosion deposits. Here again, partially sharp edges referring to both initiation and propagation along the interfaces present in the material are observable, i.e. probably the Mg 2 Zn 11 phase surrounded by oxides. The composition of the corrosion products in the pit Fig. 8. Detailed analyses of extruded materials using APT: a) Zn-2.6Mg (4h) +Ex ; b) visualization of Mg 2 Zn 11 and Zn phase interface in Zn-2.6Mg (4h) +Ex ; c) visualization of nano-size particle and Zn phase interface in Zn-2.6Mg (4h) +Ex d) Zn-2.6Mg-0.6Ag (4h) +Ex ; e) visualization of grain boundary (GB) interface with Zn2.6Mg-0.6Ag (4h) +Ex with a higher fraction of Mg ions; f) visualization of low-angle grain boundaries (LAGB) interface within Zn-2.6Mg-0.6Ag (4h) +Ex matrix with a higher fraction of Ag ions. Table 3 Bulk compositional (at %) analysis obtained by APT measurements of Zn2.6Mg (4h) +Ex and Zn-2.6Mg-0.6Ag (4h) +Ex . Zn Mg Ag O H Zn-2.6Mg (4h) þEx Bulk Zn 99.13 0.04 0.52 0.30 Precipitate I 57.80 12.48 19.00 10.72 Precipitate II 73.60 5.50 11.72 9.16 Precipitate III 94.81 2.10 1.74 1.35 Zn-2.6Mg-0.6Ag (4h) þEx Bulk Zn I 99.10 0.90   Bulk Zn II 99.09 0.92   Bulk Zn III 99.61 0.01 0.37 0.02  Precipitate I 97.09 0.03 2.79 0.09 0.01 Precipitate II 98.14 1.93 0.03  Precipitate III 88.81 0.05 11.13 0.01  Precipitate IV 97.92 0.98 1.02 0.04  Precipitate V 97.44 1.04 1.15 0.29 0.08 Precipitate VI 98.05 0.96 0.99   J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4352 Fig. 9. Zn-2.6Mg (4h) +Ex microstructure analysis and profile of chemical composition along the orange line – STEM-EDS: a, b) location 1 and b, c) location 2. Fig. 10. Mechanical properties of materials: a) Tensile engineering stress – engineering strain curves at laboratory temperature and 37 ◦C (marked by *), b) evaluated properties of studied materials. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4353 7) Silver presence in alloy supports the antibacterial effect towards S. epidermidis. Author contributions Jiˇ rí Kub´ asek – data analyses, mechanical tests, writing, review, editing, Selase Torkornoo – APT analyses, writing, review, editing, David Neˇ cas – materials preparation using SPS, microstructure analyses using OM, Ingrid McCarroll – APT analyses, Vojtˇ ech Hyb´ aˇ sek – corrosion tests, Baptiste Gault – APT data analysis, review, editing, Eva Jablonsk´ a – in-vitro biological tests, writing, ˇ Crtomir Donik – EBSD analyses, Irena Paulin – microstructure analyses using SEM, Peter Gogola – XRD analyses, Martin Kusý – XRD analyses, Zdenˇ ek Míchal – in-vitro biological tests, Jaroslav Fojt – corrosion tests, Miroslav ˇ Cavojský – materials preparation by extrusion, Jan Duchoˇ n – TEM analyses and their evaluation, Mark´ eta Jaroˇ sov´ a – EDX, WDX analyses, Jaroslav ˇ Capek – processing and interpretation of TEM data, review, editing. Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jiri Kubasek, David Necas, Vojtech Hybasek, Eva Jablonska, Jaroslav Fojt, Jaroslav Capek reports financial support was provided by Czech Science Foundation. Crtomir Donik, Irena Paulin reports financial support was provided by Slovenian Research and Innovation Agency. Miroslav Cavojsky reports financial support was provided by Ministry of Education Science Research and Sport of the Slovak Republic. Jiri Kubasek, Eva Jablonska, Jaroslav Fojt reports financial support was provided by Ministry of Education Youth and Sports of the Czech Republic. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgement This research was supported by the Czech Science Foundation (project no. 21–11439K) and by the project "Mechanical Engineering of Biological and Bio-inspired Systems", funded as project No. CZ.02.01.01/00/22_008/0004634 by Programme Johannes Amos Comenius, call Excellent Research. Furthermore, this work was carried out within the framework of the Slovenian Research Agency ARIS project N2-0182 ‘‘Development of advanced bioabsorbable Zn-based materials by powder metallurgy techniques. ‘‘and ARIS program P2 0132 ‘‘Physics and Chemistry of Metals‘‘. Baptiste Gault, Ingrid McCarroll and Selase Torkornoo are grateful to the Deutsche Forschungsgemeinschaft (DFG) for funding through Baptiste Gault’s Leibniz Award. The Slovak authors would like to thank the Vega 1/ 0531/22 project funded by the Ministry of Education, Science, Research and Sport of the Slovak Republic for the financial support and Cost action CA22147 (EU4MOFs). Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.jmrt.2025.06.185. References [1] Kabir H, Munir K, Wen C, Li Y. Recent research and progress of biodegradable zinc alloys and composites for biomedical applications: biomechanical and biocorrosion perspectives. Bioact Mater 2021;6(3):836–79. [2] Mostaed E, Sikora-Jasinska M, Drelich JW, Vedani M. Zinc-based alloys for degradable vascular stent applications. Acta Biomater 2018;71:1–23. [3] Ji C, Ma A, Jiang J, Song D, Liu H, Guo S. Research status and future prospects of biodegradable Zn-Mg alloys. J Alloy Compd 2024;993. [4] Chen Q, Thouas GA. Metallic implant biomaterials. Mater Sci Eng R Rep 2015;87: 1–57. [5] Li H, Zheng Y, Qin L. Progress of biodegradable metals. Prog Nat Sci Mater Int 2014;24(5):414–22. [6] Li HF, Xie XH, Zheng YF, Cong Y, Zhou FY, Qiu KJ, Wang X, Chen SH, Huang L, Tian L, Qin L. Development of biodegradable Zn-1X binary alloys with nutrient alloying elements Mg, Ca and Sr. Sci Rep 2015;5:1–14. [7] Jin H, Zhao S, Guillory R, Bowen PK, Yin Z, Griebel A, Schaffer J, Earley EJ, Goldman J, Drelich JW. Novel high-strength, low-alloys Zn-Mg (\textless 0.1wt \% Mg) and their arterial biodegradation. Materials science \& engineering C, Materials for biological applications 2018;84:67–79. [8] Agarwal R, Fries SG, Lukas HL, Petzow G, Sommer E, Chart TG, Effenberg G. Assessment of the Mg-Zn system. International Journal of Materials Research 1992; 83(4):216–23. [9] Suryanarayana C, Ivanov E, Boldyrev VV. The science and technology of mechanical alloying. Materials Science and Engineering: A 2001;304–306:151–8. [10] da Rocha CJ, Neto RML, Gonçalves VS, Carvalho LL, Ambrozio Filho F. An investigation of the use of stearic acid as a process control agent in high energy ball milling of Nb-Al and Ni-Al powder mixtures. Materials Science Forum 2003; 416–418:144–9. [11] Pinc J, ˇ Skol´ akov´ a A, Veˇ rt´ at P, Duchoˇ n J, Kub´ asek J, Lejˇ cek P, Vojtˇ ech D, ˇ Capek J. Microstructure evolution and mechanical performance of ternary Zn-0.8Mg-0.2Sr (wt. %) alloy processed by equal-channel angular pressing. Materials Science and Engineering: A 2021;824. [12] Narendra Kumar Y, Venkateswarlu B, Ratna Raju L, Dumpala R, Ratna Sunil B. Developing Zn-MgO composites for degradable implant applications by powder metallurgy route. Materials Letters 2021;302. [13] Bahraminasab M, Farahmand F. State of the art review on design and manufacture of hybrid biomedical materials: hip and knee prostheses. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 2017;231(9):785–813. [14] Lee K-H, Lee J-M, Park J-H, Kim B-M. Fabrication of miniature helical gears by powder extrusion using gas atomized Zn–22%Al powder. Transactions of Nonferrous Metals Society of China 2012;22(6):1313–21. [15] Qiu CL, Attallah MM, Wu XH, Andrews P. Influence of hot isostatic pressing temperature on microstructure and tensile properties of a nickel-based superalloy powder. Materials Science and Engineering: A 2013;564:176–85. [16] Sotoudeh Bagha P, Khaleghpanah S, Sheibani S, Khakbiz M, Zakeri A. Characterization of nanostructured biodegradable Zn-Mn alloy synthesized by mechanical alloying. J Alloy Compd 2018;735:1319–27. [17] Yan Y, Liu H, Fang H, Yu K, Zhang T, Xu X, Zhang Y, Dai Y. Effects of the intermetallic phases on microstructure and properties of biodegradable magnesium matrix and zinc matrix prepared by powder metallurgy. Materials Transactions 2018;59(11):1837–44. [18] Li XY, Zhang ZH, Cheng XW, Huo GJ, Zhang SZ, Song Q. The development and application of spark plasma sintering technique in advanced metal structure materials: a review. Powder Metallurgy and Metal Ceramics 2021;60(7–8):410–38. [19] Cheng Y, Cui Z, Cheng L, Gong D, Wang W. Effect of particle size on densification of pure magnesium during spark plasma sintering. Advanced Powder Technology 2017;28(4):1129–35. [20] Cui Z, Luo M, Zhang Y, Gong D, Wang W, Wang J. Fabrication of high strength and plasticity of Zn-Mg composites with core–shell structure by spark plasma sintering. Materials Letters 2020;279. [21] Yang Y, Yuan F, Gao C, Feng P, Xue L, He S, Shuai C. A combined strategy to enhance the properties of Zn by laser rapid solidification and laser alloying. J Mech Behav Biomed Mater 2018;82:51–60. [22] Voshage M, Megahed S, Schückler PG, Wen P, Qin Y, Jauer L, Poprawe R, Schleifenbaum JH. Additive manufacturing of biodegradable Zn-xMg alloys: effect of Mg content on manufacturability, microstructure and mechanical properties. Materials Today Communications 2022;32. [23] Qin Y, Liu A, Guo H, Shen Y, Wen P, Lin H, Xia D, Voshage M, Tian Y, Zheng Y. Additive manufacturing of Zn-Mg alloy porous scaffolds with enhanced osseointegration: in vitro and in vivo studies. Acta Biomater 2022;145:403–15. [24] Vojtech D, Kubasek J, Serak J, Novak P. Mechanical and corrosion properties of newly developed biodegradable Zn-based alloys for bone fixation. Acta Biomaterialia 2011;7(9):3515–22. [25] Lutterotti L, Matthies S, Wenk HR. MAUD (Naturiel Analysis Using Diffraction): a user friendly JAVA program for Rietveld texture analysis and more. 1999. p. 1599–604. [26] Fischer J, Pr¨ ofrock D, Hort N, Willumeit R, Feyerabend F. Improved cytotoxicity testing of magnesium materials. Materials Science and Engineering: B 2011;176 (11):830–4. [27] ˇ Skol´ akov´ a A, Pinc J, Jablonsk´ a E, ˇ Skol´ akov´ a T, Veˇ rt´ at P, Janebov´ a B, Kutov´ a A, ˇ Capek J, Hosov´ a K, Vojtˇ ech D, Kub´ asek J. A zinc phosphate layered biodegradable Zn-0.8Mg-0.2Sr alloy: characterization and mechanism of hopeite formation. Surface and Coatings Technology 2024;487. [28] Necas D, Marek I, Pinc J, Vojtech D, Kubasek J. Advanced zinc-magnesium alloys prepared by mechanical alloying and spark plasma sintering. Materials (Basel) 2022;15(15). [29] Jarzębska A, Bieda M, Maj Ł, Chulist R, Wojtas D, Strąg M, Sułkowski B, Przybysz S, Pachla W, Sztwiertnia K. Controlled grain refinement of biodegradable Zn-Mg alloy: the effect of magnesium alloying and multi-pass hydrostatic extrusion preceded by hot extrusion. Metallurgical and Materials Transactions A 2020;51 (12):6784–96. [30] Kubasek J, Vojtech D, Jablonska E, Pospisilova I, Lipov J, Ruml T. Structure, mechanical characteristics and in vitro degradation, cytotoxicity, genotoxicity and mutagenicity of novel biodegradable Zn-Mg alloys. Mater Sci Eng C-Mater Biol Appl 2016;58:24–35. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4360 [31] Kim S-H, Bhatt S, Schreiber DK, Neugebauer J, Freysoldt C, Gault B, Katnagallu S. Understanding atom probe’s analytical performance for iron oxides using correlation histograms and ab initio calculations. New Journal of Physics 2024;26 (3):033021. [32] Gault B, Saksena A, Sauvage X, Bagot P, Aota LS, Arlt J, Belkacemi LT, Boll T, Chen Y-S, Daly L, Djukic MB, Douglas JO, Duarte MJ, Felfer PJ, Forbes RG, Fu J, Gardner HM, Gemma R, Gerstl SSA, Gong Y, Hachet G, Jakob S, Jenkins BM, Jones ME, Khanchandani H, Kontis P, Kr¨ amer M, Kühbach M, Marceau RKW, Mayweg D, Moore KL, Nallathambi V, Ott BC, Poplawsky JD, Prosa T, Pundt A, Saha M, Schwarz TM, Shang Y, Shen X, Vrellou M, Yu Y, Zhao Y, Zhao H, Zou B. Towards establishing best practice in the analysis of hydrogen and deuterium by atom probe tomography. Microscopy and Microanalysis December 2024;30(6): 1205–20. [33] Devaraj A, Colby R, Hess WP, Perea DE, Thevuthasan S. Role of photoexcitation and field ionization in the measurement of accurate oxide stoichiometry by laserassisted atom probe tomography. The Journal of Physical Chemistry Letters 2013;4 (6):993–8. [34] Araullo-Peters VJ, Gault B, Shrestha SL, Yao L, Moody MP, Ringer SP, Cairney JM. Atom probe crystallography: atomic-scale 3-D orientation mapping. Scripta Materialia 2012;66(11):907–10. [35] Yu Y, Zhang S, Mio AM, Gault B, Sheskin A, Scheu C, Raabe D, Zu F, Wuttig M, Amouyal Y, Cojocaru-Mir´ edin O. Ag-segregation to dislocations in PbTe-based thermoelectric materials. ACS Applied Materials & Interfaces 2018;10(4):3609–15. [36] Kwiatkowski da Silva A, Leyson G, Kuzmina M, Ponge D, Herbig M, Sandl¨ obes S, Gault B, Neugebauer J, Raabe D. Confined chemical and structural states at dislocations in Fe-9wt%Mn steels: a correlative TEM-atom probe study combined with multiscale modelling. Acta Materialia 2017;124:305–15. [37] Kub´ asek J, Pinc J, Hosov´ a K, Strakov´ a M, Moln´ arov´ a O, Duchoˇ n J, Neˇ cas D, ˇ Cavojský M, Knapek M, Godec M, Paulin I, Vojtˇ ech D, ˇ Capek J. The evolution of microstructure and mechanical properties of Zn-0.8Mg-0.2Sr alloy prepared by casting and extrusion. J Alloy Compd 2022;906. [38] Klima K, Ulmann D, Bartos M, Spanko M, Duskova J, Vrbova R, Pinc J, Kubasek J, Vlk M, Ulmannova T, Foltan R, Brizman E, Drahos M, Beno M, Machon V, Capek J. A complex evaluation of the in-vivo biocompatibility and degradation of an extruded ZnMgSr absorbable alloy implanted into rabbit bones for 360 days. International Journal of Molecular Sciences 2021;22(24). [39] Zhao C, Chen X, Pan F, Wang J, Gao S, Tu T, Liu C, Yao J, Atrens A. Strain hardening of as-extruded Mg-xZn (x =1, 2, 3 and 4 wt%) alloys. Journal of Materials Science & Technology 2019;35(1):142–50. [40] Zhang XG. Electrochemical thermodynamics and kinetics. In: Zhang XG, editor. Corrosion and electrochemistry of zinc. Boston, MA: Springer US; 1996. p. 19–63. [41] Zhang XG. Passivation and surface film formation. In: Zhang XG, editor. Corrosion and electrochemistry of zinc. Boston, MA: Springer US; 1996. p. 65–91. [42] Vaidya M, Muralikrishna GM, Murty BS. High-entropy alloys by mechanical alloying: a review. Journal of Materials Research 2019;34(5):664–86. [43] Capek J, Kubasek J, Pinc J, Drahokoupil J, Cavojsky M, Vojtech D. Extrusion of the biodegradable ZnMg0.8Ca0.2 alloy - the influence of extrusion parameters on microstructure and mechanical characteristics. J Mech Behav Biomed Mater 2020; 108:16. [44] Pinc J, Skol´ akov´ a A, Hyb´ asek V, Msallamov´ a S, Vert´ at P, Ashcheulov P, Vondr´ acek M, Duchon J, McCarroll I, Hyvl M, Banerjee S, Drahokoupil J, Kub´ asek J, Vojtech D, Capek J. A detailed mechanism of degradation behaviour of biodegradable as-ECAPed Zn-0.8Mg-0.2Sr with emphasis on localized corrosion attack. Bioactive Materials 2023;27:447–60. [45] Burmeister CF, Hofer M, Molaiyan P, Michalowski P, Kwade A. Characterization of stressing conditions in a high energy ball mill by discrete element simulations. Processes 2022;10(4). [46] Martelli S, Di Nunzio PE. Powder ball milling: an energy balance approach to particle size reduction. Journal of Materials Research 2024;40(2):292–308. [47] Schneibel JH, Heilmaier M. Hall-petch breakdown at elevated temperatures. Materials Transactions 2014;55(1):44–51. [48] Bignon M, Bernacki M. Particle pinning during grain growth—a new analytical model for predicting the mean limiting grain size but also grain size heterogeneity in a 2D polycrystalline context. Acta Materialia 2024;277. [49] Jarzębska A, Bieda M, Kawałko J, Rogal Ł, Koprowski P, Sztwiertnia K, Pachla W, Kulczyk M. A new approach to plastic deformation of biodegradable zinc alloy with magnesium and its effect on microstructure and mechanical properties. Materials Letters 2018;211:58–61. [50] Hern´ andez-Escobar D, Rahman ZU, Yilmazer H, Kawasaki M, Boehlert CJ. Microstructural evolution and intermetallic formation in Zn-Mg hybrids processed by High-Pressure Torsion. Philosophical Magazine 2018;99(5):557–84. [51] Figueiredo RB, Kawasaki M, Langdon TG. Seventy years of Hall-Petch, ninety years of superplasticity and a generalized approach to the effect of grain size on flow stress. Progress in Materials Science 2023;137. [52] Chen C, Fan S, Niu J, Huang H, Jin Z, Kong L, Zhu D, Yuan G. Alloying design strategy for biodegradable zinc alloys based on first-principles study of solid solution strengthening. Materials & Design 2021;204. [53] Kammerer CC, Behdad S, Zhou L, Betancor F, Gonzalez M, Boesl B, Sohn YH. Diffusion kinetics, mechanical properties, and crystallographic characterization of intermetallic compounds in the Mg–Zn binary system. Intermetallics 2015;67: 145–55. [54] Liu H, Huang H, Zhang Y, Xu Y, Wang C, Sun J, Jiang J, Ma A, Xue F, Bai J. Evolution of Mg–Zn second phases during ECAP at different processing temperatures and its impact on mechanical properties of Zn-1.6Mg (wt.%) alloys. J Alloy Compd 2019;811. [55] Deschamps A, Hutchinson CR. Precipitation kinetics in metallic alloys: experiments and modeling. Acta Materialia 2021;220. [56] Lin J, Chen Y, Dai Y, Zhang X, Zhang D, Li Y, Wen C. Mechanical properties, degradation action, and biocompatibility of in situ nanoparticle-reinforced Mg(x) Zn(y)/Zn composite prepared via roll bonding. Acta Biomater 2025;194:514–29. [57] Kubasek J, Vojtˇ ech D. Zn-based alloys as an alternative biodegradable materials. Proc Metal 2012;5:23–5. [58] Tong X, Zhang D, Lin J, Dai Y, Luan Y, Sun Q, Shi Z, Wang K, Gao Y, Lin J, Li Y, Dargusch M, Wen C. Development of biodegradable Zn–1Mg–0.1RE (RE =Er, Dy, and Ho) alloys for biomedical applications. Acta Biomater 2020;117:384–99. [59] Pan C, Sun X, Xu G, Su Y, Liu D. The effects of β-TCP on mechanical properties, corrosion behavior and biocompatibility of β-TCP/Zn-Mg composites. Materials Science and Engineering: C 2020;108:110397. [60] Zhao R, Ma Q, Zhang L, Zhang J, Xu C, Wu Y, Zhang J. Revealing the influence of Zr micro-alloying and hot extrusion on a novel high ductility Zn–1Mg alloy. Materials Science and Engineering: A 2021;801:140395. [61] Li R, Ding Y, Zhang H, Lei J, Shen Y. Effective strengthening and toughening in Zn–1Mg alloy with bimodal grain structure achieved by conventional extrusion. Materials Science and Engineering: A 2022;854:143850. [62] García-Mintegui C, C´ ordoba LC, Buxadera-Palomero J, Marquina A, Jim´ enezPiqu´ e E, Ginebra M-P, Cortina JL, Pegueroles M. Zn-Mg and Zn-Cu alloys for stenting applications: from nanoscale mechanical characterization to in vitro degradation and biocompatibility. Bioactive Materials 2021;6(12):4430–46. [63] Pachla W, Przybysz S, Jarzębska A, Bieda M, Sztwiertnia K, Kulczyk M, Skiba J. Structural and mechanical aspects of hypoeutectic Zn–Mg binary alloys for biodegradable vascular stent applications. Bioactive Materials 2021;6(1):26–44. [64] Cui J, Liang H, Chen S, Shao Y, Chen H, Yang M, Yang Y. Recent progress and perspectives in laser additive manufacturing of biodegradable zinc alloy. Journal of Materials Research and Technology 2024/11/01;33. [65] Voshage M, Megahed S, Schückler PG, Wen P, Qin Y, Jauer L, Poprawe R, Schleifenbaum JH. Additive manufacturing of biodegradable Zn-xMg alloys: effect of Mg content on manufacturability, microstructure and mechanical properties. Materials Today Communications 2022;32:103805. [66] Balog M, Marques de Castro M, ˇ Capek J, ˇ Svec Jr P, Tak´ aˇ cov´ a M, Cs´ aderov´ a L, Sedl´ aˇ ckov´ a E, ˇ Svastov´ a E, ˇ Skol´ akov´ a A, Dvorský D, Pinc J, Hyb´ aˇ sek V, Kub´ asek J, Kríˇ zik P, Skiba J, Bajana O, Hassan Ibrahim AM. Suppression of mechanical instability in bioabsorbable ultrafine-grained Zn through in-situ stabilization by ZnO nanodispersoids. Journal of Materials Research and Technology 2023;25: 4510–27. [67] Bednarczyk W, Wtroba M, Kawako J, Baa P. Can zinc alloys be strengthened by grain refinement? A critical evaluation of the processing of low-alloyed binary zinc alloys using ECAP. Materials Science and Engineering A 2019;748(December 2018):357–66. [68] Jablonska E, Mrazkova L, Kubasek J, Vojtech D, Paulin I, Ruml T, Lipov J. Characterization of hFOB 1.19 cell line for studying Zn-based degradable metallic biomaterials. Materials (Basel) 2024;17(4). [69] ˇ Svagrov´ a K, Horkavcov´ a D, Jablonsk´ a E, Helebrant A. Titania-based sol-gel coatings with Ag, Ca-P applied on titanium substrate developed for implantation. J Biomed Mater Res B Appl Biomater 2022;110(1):115–24. J. Kub´ asek et al. Journal of Materials Research and Technology 37 (2025) 4345–4361 4361