Ultrafine grain refinement of AlMn1Cu and AZ 31 alloys by SPD process

ARCHIVES OF METALLURGY AND MATERIALS Volume 59 2014 Issue 1 DOI: 10.2478/amm-2014-0060 S. RUSZ∗, L. CIZEK∗, M. SALAJKA∗, S. TYLSAR∗, J.KEDRON∗, V. MICHENKA∗∗ , T. DONIC∗∗∗ , E. HADASIK∗∗∗∗ , M. KLOS∗ ULTRAFINE GRAIN REFINEMENT OF ALMn1Cu AND AZ 31 ALLOYS BY SPD PROCESS ROZDROBNIENIE ZIARN STOPÓW AlMn1Cu I AZ 31 DO ROZMIARÓW ULTRAMETRYCZNYCH Z ZASTOSOWANIEM PROCESU SPD One o he ways o he mo e e ec i e use o me allic ma e ials is hei p ocessing by o ming. A p esen in his he a ea he use o he p ocess o se e e plas ic de o ma ion (SPD p ocess), leading o a e inemen o he s uc u e (ma e ials wi h UFG s uc u e) and hus o achie emen o highe le el o hei u ili y alue, is expanding. AlMn1Cu alloy is comme cially p oduced aluminum alloy by he company Al In es B idlicna ( he cas s ip wi h a mild educ ion by olling up o 10% o he hickness o 10 and 15 mm, which has i s uses especially in enginee ing. AZ31 alloy is comme cially p oduced aluminum alloy a e cas ing and ex usion a 400◦C on inal od wi h 20 mm diame e . Fo expe imen al pu poses om he bel s o alloys he es samples o he unde lying dimensions o 10×10 mm leng h 40 mm (geome y wi h channel de lec ion 20◦) and 15×15 mm leng h 60 mm (geome y wi h helix ma ix) in he di ec ion o olling we e made. All h ee ins umen s a e made o high ool s eel - HOTVAR. Fo compa e he in luence o geome y ECAP ool on s uc u e e ining was used AlMn1Cu and AZ31 alloys we e used h ee specially made ools ECAP, di e ing mainly in he cons uc ion design. Keywo ds: se e e plas ic de o ma ion, ECAP me hod, ha dness, mic os uc u e Jednym ze sposobów ba dziej e ek ywnego ksz ał owania plas ycznego me ali jes me oda dużych odksz ałceń plas ycz- nych. Ak ualnie do ego celu wyko zys ywany jes p oces SPD, w wyniku k ó ego osiąga się wysokie wa ości odksz ałcenia ma e iału z ul a d obnozia nis ą s uk u ą. P owadzi o do wz os u właściwości wy zymałościowych, p zy nieznacznym obniże- niu plas yczności. W a ykule p zeds awiono wyniki badań dwóch s opów – s op aluminium AlMn1Cu, k ó y jes p odukowany w o mie blachy g ubości 10 lub 15 mm z zas osowaniem w p zemyśle maszynowym o az s op magnezu AZ31, k ó y po od- laniu jes wyciskany w empe a u ze 400◦C z p ę a o ś ednicy 60 mm na ś ednicę 20 mm. Do ekspe ymen ów uży o p óbek o ozmia ach 10×10-40 mm z odchyleniem kanału na zędzia ECAP o 20◦od kie unku poziomego o az p óbki o ozmia ach 15×15-60 mm z nową geome ią kanału na zędzia ECAP (część kanału w ksz ałcie ś uby) dla zwiększenia odksz ałcenia w poszczególnych p zejściach p óbki na zędziem ECAP. Uzyskane wyniki wa dości o az s uk u y, p zy użyciu wyżej podanych geome ii na zędzia ECAP, były po ównywane oddzielnie u obu s opów. 1. In oduc ion The p ocess o plas ic de o ma ion, which leads o a e- inemen o he s uc u e, depends on se e al ac o s. The mos impo an mechanism o cold and ho plas ic de o ma ion is disloca ion slip, which is he mos e iden unde he shea s ess load. I is one o he main p e- equisi es a designing he me hods based on he use o he SPD p ocess. The e ec was obse ed mainly in me als and alloys wi h cubic ace-cen ed la ice, cha ac e ised by a high numbe o slip sys ems (Al, Cu, Ni) [1,4,5,6]. In addi ion o he men ioned la ice s uc u e he ollowing ac o s a e in ol ed: he s uc u e be o e de o ma ion (g ain size, mic os uc u e), he second phase pa icles, s ain a e and empe a u e o de o ma ion, magni ude o de o ma ion, he ou e o de o ma ion. Mechanisms o g ain e inemen a y depending on he magni ude o de o ma ion di ided he in luence o he magni ude o an inc ease o de o ma ion in o ou a eas [2,3]. This conce ns e alua ion o esul s achie ed du ing de o ma ion o me als wi h cubic ace-cen ed la ice ECAP (ECAP-p inciple – see below a desc ip ion o he p o- posed p ojec ), using he de o ma ion ou e BC: small s ain in ensi y (εV M <2), small o mode a e s ain in ensi y (εV M = 2 - 4), mode a e o high s ain in ensi y (εV M =4 - 6), ex eme s ain in ensi y – SPD (εV M >6) [5]. Ul a ine-g ained ma e ials (UFG) a e de ined as poly-c ys als wi h a e age g ain size in he ange om 100 nm - 1000 nm, i.e. less han 1µm. UFG ma e ials include also nano-ma e ials wi h g ain sizes anging om 10 nm - 100 nm. G owing in e es in UFG ma e ials a ises mainly o wo ea- ∗VSB – TECHNICAL UNIVERSITY OF OSTRAVA, FACULTY OF MECHANICAL ENGINEERING, CZ 708 33 OSTRAVA PORUBA, CZECH REPUBLIC ∗∗ RESEARCH INSTITUTE OF IRON AND METALLURGY DOBRA, CZ 738 01 DOBRA, CZECH REPUBLIC ∗∗∗ TECHNICAL UNIVERSITY OF ZILINA, 010 26 ZILINA, SLOVAKIA ∗∗∗∗ SILESIAN UNIVERSITY OF TECHNOLOGY KATOWICE, FACULTY OF MATERIALS ENGINEERING AND METALLURGY, KATOWICE, POLAND B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM 360 sons. Fi s ly, i is known ha in all he alloys he Hall-Pe ch mechanism [4] con ibu es o s eng hening o he ma e ial a oom empe a u e acco ding. The basic me hods o p oduc ion o UFG ma e ials a e he ollowing [3,7]: ECAP – Equal Channel Angula P essing DCAP – Dissimila Channel Angula P essing HPT – High P essu e To sion CCDC – Cyclic Channel Die Comp ession CEC – Cyclic Ex usion Comp ession CONFORM – Con inuous Ex usion Fo ming ARB – Accumula i e Roll Bonding CGP – Cons ained G oo e P essing TE – Twis Ex usion Designing a new concep o geome y ool The ECAP me hod is based on ex usion o he sample h ough he ool wi h an in e nal L-shaped channel, wi hou any change o c oss-sec ion o he sample, as i is e iden om Figu e 1. The sample is inse ed om abo e in o he e ical channel and hen ex uded h ough he ool [7,14]. This ope - a ion is hen epea ed in o de o achie e he equi ed deg ee o de o ma ion o he ma e ial leading o a e inemen o he s uc u e. I is possible o use in he p ocess a ious ypes o changes o he ou e o de o ma ion [11]. Fig. 1. The p inciple o he ECAP me hod [7] New concep – me hod ECAP wi h wis ex usion TE is based on ex usion o he sample o p isma - ic c oss-sec ion h ough he ool wi h he p o ile consis ing o wo p isma ic pa s sepa a ed by a helical pa (Fig. 2). C oss-sec ion a TE emains unchanged. This ea u e makes i possible o ex ude he sample epea edly in o de o ac- cumula e he s ain needed o change he mic o-s uc u e and mechanical p ope ies o he sample ma e ial. Fig. 2. P inciple o he Twis Ex usion P ocess [10,12] Technological possibili ies o he TE me hod compa ed wi h he ECAP me hod [12]. Magni ude o e mina ion o he de o med a ea o he sample a he inpu and ou pu pa o he sample is much lowe in TE han in ECAP. This is a ea u e, which is e y impo an o epea ing o passes. Change o he sample p o ile occu s a he cen al pa o he axial channel TE can be easily ins alled on he s anda d equipmen o he p ess by eplacemen o adi ional ools by he ool wi h o- a y channel (helix). Tool (TE) does no change he di ec ion o mo emen o he sample, which enables i s simple inclu- sion in o he exis ing ools on he p esses and hus in eg a ion o his equipmen in o a p oduc ion line [6,13]. The p oposed p ojec will e i y he o ally new concep o he o ming ool – called ECAP +TE (ECAP ool wi h buil -helix in he ho izon- al channel – Fig. 3). This new app oach will make i possible o signi ican ly inc ease he e iciency o he p ocess o se e e plas ic de o ma ion (SPD). The ma e ial will be s eng hened e y in ensely, allowing us o achie e a high deg ee o de o - ma ion o ma e ial a a lowe numbe o passes h ough he o ming ool [8]. A he same ime high homogenei y o he s uc u e will be achie ed. Fig. 3. Inse o he ECAP ool wi h buil -in helix 2. Expe imen al ma e ials AlMn1Cu alloy is comme cially p oduced aluminum al- loy by he company Al In es ( he cas s ip wi h a mild e- duc ion by olling up o 10% o he hickness o 10 and 15 mm, which has i s uses especially in enginee ing. Chemical composi ion o he AlMn1Cu alloy is gi en in Tab.1. AZ31 alloy is comme cially p oduced aluminum alloy a e cas ing and ex usion a 400◦C on inal od wi h 20 mm diame e . Chemical composi ion o he AZ31 alloy is gi en in Tab.2. Fo expe imen al pu poses om he bel s o alloys he es samples o he unde lying dimensions o 10×10 mm leng h 40 mm (geome y wi h channel de lec ion 20◦) and 15×15 mm leng h 60 mm (geome y wi h helix ma ix) in he di ec ion o olling we e made. TABLE 1 Chemical composi ion o AlMn1Cu alloy (weigh %) Si Fe Cu Mn O he Al 00.55 00.45 00.15 11.1 00.15 Res TABLE 2 Chemical composi ion o he AZ31 alloy (weigh %) Al Zn Cu Mn O he Mg 33.07 00.765 00.0016 00.246 00.15 Res B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM 361 3. ECAP design ools used in he expe imen s Fo compa e he in luence o geome y ECAP ool on s uc u e e ining was used AlMn1Cu and AZ31 alloys we e used h ee specially made ools ECAP, di e ing mainly in he cons uc ion design. All h ee ins umen s a e made o high ool s eel – HOTVAR. The i s ool used in he expe imen is a classic ool o ECAP wi h e ical and ho izon al channel connec ions a an angle ϕ=90◦, ou e adius R1 =2.5 mm, inne adius R2 =0.2 mm and 10×10 mm c oss-sec ion o he channel (Fig. 1). The second ool is based on geome y om he i s ype [9]. To he modi ica ion o ins umen s occu ed in he ho izon al pa o channel – de lec ion o he ho izon al channel wi h 20◦a ound axis ”z” (Fig. 4). The hi d modi i- ca ion o ool used in he expe imen is a new ool o ECAP wi h helix pa in he ho izon al pa o channel (Fig. 5). The helix angle is 10◦and 30◦. Value o he ou e channel adius is R1 =2.5 mm, inne adius R2 =0.5 mm and he angles o he channel ha e alues ϕ=90◦,ψ=90. The main bene i o he new geome y is a ising o he backp essu e and he inc easing deg ee o de o ma ion. The ools used a e shown in Fig. 4,5,6 and 7. Fig. 4. The ho izon al channel wi h 20◦a ound axis Fig. 5. ECAP ool wi h helix ma ix Fig. 6. Gene al iew on used ECAP ools Fig. 7. Shape o punches 4. In luence o he numbe o passes on he s ess –s ain cu es The esul s o expe imen s conduc ed on hyd aulic p ess DP 1600 kN, was shown a signi ican e ec modi ica ion o he geome y ools ECAE cu es de o mable esis ance and hus ha dening he AlMn1Cu and magnesium AZ31 alloys each channel passes. Acco ding o he assump ions unde lying he inc ease de o mable esis ance occu s in all he ins umen s o ECAP wi h inc easing numbe o passes. Fig. 8 shows selec ed eadings s ess-s ain cu es a e selec ed passes h ough he channel o AlMn1Cu alloy. Ve y good esul s we e achie ed in bo h alloys using geome y ools wi h embedded helix a e 1s and 5 h passes h ough he ECAP ool. Fig. 9 show selec ed eadings s ess-s ain cu es a e selec ed passes h ough he channel o magnesium alloy AZ31[8,9]. Fig. 8. S ess-s ain cu es a) a e he i s and b) a e he i h pass h ough ECAP B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM 362 Fig. 9. S ess-s ain cu es ECAP wi h helix ma ix 5. Me allog aphic analysis Fo me allog aphic analyses a se ies o samples a e passes we e p epa ed by he cu ing pe pendicula o o m- ing di ec . Me allog aphic analysis o he inal s uc u e o he AlMn1Cu alloy was pe o med me hods o ligh mic oscopy, TEM and SAED. Fo he AZ31 alloy he me allog aphic analy- sis by ligh mic oscopy was ca ied ou . Me allog aphic analy- sis on ligh mic oscopy NEOPHOT 2 was pe o med. A e he usual me allog aphic p epa a ion he AlMn1Cu alloy un- de wen he elec oly ic e ching and magnesium alloy AZ31 was e ched. Resul s o me allog aphic analysis o samples AlMn1Cu alloy a e shown in Fig. 10 and 11 ( esul s o ligh mic oscopy). As i is seen om Fig. 10 and 11 he s ep o g ain size a ises wi h numbe o passes. Me allog aphic analysis TEM and SAED o AlMn1Cu alloy shows Fig. 12 and 13: a) ini ial s a e; b) a e 5 h pass classical ECAP ool; c) a e 5 h pass ECAP ool wi h de lec ion 20◦; d) a e 5 h pass ECAP ool wi h helix 10◦[8,9]. Fig. 10. Resul s o me allog aphic analysis o he AlMn1Cu alloy a) ini ial s a e, b) 3 d pass, c) 5 h pass Fig. 11. Resul s o me allog aphic analysis o he magnesium alloy AZ31, a) ini ial s a e, b) 3 d pass, c) 5 h pass Fig. 12. S uc u e o he AlMn1Cu alloy (pe o med me hods o TEM), a) ini ial s a e, b) 5 h pass, channel wi hou de lec ion, c) 5 h pass, wi h 10◦helix B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM 363 Fig. 13. S uc u e o he AlMn1Cu alloy (pe o med me hods o SAED), a) ini ial s a e, b) 5 h pass, channel wi hou de lec ion, c) 5 h pass, wi h 10◦helix 6. Discussion Tes ing pla es wi h a hickness o 3 mm we e used om samples a e 5 h pass. The pla es we e hen cu and polished o a inal hickness o 0.13-0.15 mm. AlMn1Cu alloy s uc u e consis s o g ains o app oxima ely he same size [8,9]. These g ains con ain c ys als o Mn and Cu and in Fig. 12a a e colo ed g ay o black. The basic ma ix o Al ac ing like p e- cipi a es, which ein o ce he ma e ial and p e en seconda y g ain g ow h. The exis ence o p ecipi a es is e y impo an , because pu e aluminum has a endency o ECAP p ocess, g ain coa sening and loss o mechanical p ope ies achie ed. Ini ial g ain size eached alues o he o de o 150-200 µm. The i h classic ex usion ool wi hou de lec ion o med small g ains wi h la ge diso ien a ion o he median size o 0,5 µm o 0,7 µm (Fig. 12 b) [8,9]. O igina ed he e many in e me al- lic inclusions in he icini y o small g ains. Due o he pa - ial ec ys alliza ion o small de ec s o med wi hin he g ains and showed he he e ogenei y o he s uc u e he e. shows a ine-g ained s uc u e wi h mean g ain size o 0,3 µm o 0,6 µm and high diso ien a ion be ween he g ains. A e he e a lo o i on-con aining in e me allic inclusions o up o 5 µm. The expe imen al e i ica ion o he ECAP ools wi h 10◦he- lix in he ho izon al pa o he channel was achie ed e en wi h he la ges inc ease de o mable esis ance du ing es ing, e inemen o la ge s uc u es AlMn1Cu alloy (see Fig. 12 c). Calling back p essu e by o a ion he ho izon al channel o 10◦was o so en he ma e ial in g ain size 250 nm [8,9]. Resul s o TEM analysis a e e i ied using by SAED me hod (see Fig. 13 a,b,c). 7. Ha dness Fo he e alua ion o ha dness o o med ma e ial was used by Vicke s ha dness es , when in es iga ed in he sample we e ca ied ou i e s i ches on he su ace and cen al po - ions o he sample. Ini ial ha dness o he alloy AlMn1Cu al- eady achie ed a signi ican inc ease a e om 1s o 3 d pass all o he ins umen s used ECAP me hods. When you make hese measu emen s he e was a g adual inc ease in ha dness wi h inc easing numbe o passages. A e 5 h esp. 6 h passes occu s in all h ee ools o inc ease ha dness o he alloy o almos 100% om baseline in bo h alloys (see Fig. 14 a,b) Fig. 14. Resul s o ha dness, a) AlMn1Cu alloy, b) AZ 31 alloy 8. Conclusion The main aim o he expe imen s is a e inemen o he s uc u e o alloys AlMn1Cu using he minimum numbe o ECAP passes wi h special ools [8,9]. To inc ease he de- g ee o dis o ion, he eby achie ing he desi ed s uc u e is an impo an ac o in app op ia e modi ica ion ool geome y. Geome ic adjus men o ins umen s is pa icula ly e iden in he new ins umen ECAP helix is loca ed 10◦and 30◦in he ho izon al pa o he channel, which shows an o e all inc ease in e iciency o he SPD p ocess and ob ain signi ican ly be - e mechanical p ope ies o AlMn1Cu and AZ31 alloys [8,9]. The expe imen al esul s con i med he achie emen o e y good g ain e inemen o he s uc u e in bo h alloys. S uc u al design ools ECAP wi h inse ed helix (pi ch angle o 10 and 30◦) subs an ially inc eases he e iciency o he p oduc ion B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM 364 UFG s uc u e. Especially o AZ31 Mg alloy is gi en e y impo an inding. I is well-known ha g ain e inemen in Mg alloys is di icul o achie e a lowe empe a u es (abou 200◦C) [15]. The knowledge achie ed in alloy AZ31 also wan o check o o he ypes o magnesium alloys used in ae ospace and mili a y indus ies. Acknowledgemen s The esea ch wo k sponso ed by p ojec o Minis y o Indus y and T ade No. 2A-1TP1/124 and he p ojec o Minis y o Educa- ion, You h and spo s o Czech Republic, p ojec Nano eam VSB-TU Os a a, CZ.1.07/2.3.00/20.0038 and he p ojec Financial suppo o S uc u al Funds in he Ope a ional P og amme – Inno a i e Econ- omy (IE OP) inanced om he Eu opean Regional De elopmen Fund – P ojec ”Mode n ma e ial echnologies in ae ospace indus- y”, No POIG.01.01.02-00-015/08-00. REFERENCES [1] M.Y. G u k i n, O idko and al. Theo e ical models o plas ic de o ma ion p ocesses in nano-c ys alline ma e ials. Re . Ad . Ma e . Sci., 2, 80-102 (2001). [2] R. S o n g, D. P o n g e, D. R a a b e, G ain Bounda y Cha ac- e iza ion and G ain Size Measu emen in an Ul a ine G ained S eel, Max-Plank Ins i u o Eisen o schung, D¨ usseldo , Ge - many, Z. Me allkd 95, 6, 513-517 (2004). [3] M. B e a, D. O l o , P. P a n g n e l l, In e na ional Jou - nal o Ma e ials Resea ch 98, 200-204 (2007). [4] N.J. P e c h, J. I on S eel Ins . 174, 25 (1953). [5] A.H. C o e l l, T ans. TMS-AIME 212, 192 (1958). [6] M.A. M e y e s, D.J. B e n s o n, H.H. F u, in: Ad anced Ma e ials o he21s Cen u y, (Y. W. Chung, D. C. Dunand, P. K. Liaw, and G. B. Olson, eds.), The Mine als, Me als, and Ma e ials Socie y, Wa endale, PA (1999), p. 499. [7] R.Z. Va l i e , Recen De elopmen s o Se e e Plas ic De o - ma ion Techniques o P ocessing Bulk Nano-s uc u ed Ma e- ials, Ma e ials Science Fo um 579, 1-14 (2008). [8] S. R u s z, L. C i z e k, J. K e d o n, S. Ty l s a , M. S a l a - j k a, J. D u k i e w i c z, M. K l o s, E. H a d a s i k, S uc u e o AZ31 Magnesium alloy a e ECAP p ocessing. In Jou nal o T ends in he De elopmen o Machine y and Associa ed Technology 16, 1, 51-54 (2012), ISSN 2303-4009. [9] S. R u s z, V. M i c h e n k a, K. M a l a n i k, M. S a l a j k a, S. Ty l s a , J. K e d o n, In es iga ion o ex eme de o ma- ion condi ions on me als submic os uc u e and es ing me h- ods o diagnos ic hei echnological p ope ies, Final P ojec Repo No. Well. 2A 1TP1/124, p. 1-117 (2011). [10] V. Va y u k h i n, Y. B e y g e l z i m e , B. E o s, Nanos- uc u ed Ma e ials by Twis Ex usion and High P essu e To - sion. Ma e ials Science Fo um A584-586, 102-107 (2008). [11] A.V. N a g a s e k h a , S.C. Yo o n, Y. T i c k - H o n, H.S. K i m, An expe imen al e i ica ion o he ini e elemen model- ing o equal channel angula p essing, Compu a ional Ma e ials Science 46, 347-351 (2009). [12] V. Va y u k h i n, Y. B e y g e l z i m e , R. K u l a g i n, O. P o k o ’ e a, A. R e s h e o , Twis Ex usion: Funda- men als and Applica ions, Ma e ials Science Fo um 2- ol. Se 667-669, 31-38 (2011), ISSN 0255-5476. [13] F.Z. U y a s h e , S ain Compa ibili y and Nanos uc u ing o Bulk Me allic Ma e ials ia Se e e Plas ic De o ma ion, Ma- e ials Science Fo um 2- ol. Se 667-669, 45-50 (2011), ISSN 0255-5476. [14] Z.C. D u a n, T.G. L a n g d o n, E ec o a Special ECAP Die Con igu a ion on Mic oha dness Dis ibu ions in Pu e Alu- minum, Ma e ials Science Fo um 2- ol. Se 667-669, 69-74 (2011), ISSN 0255-5476. [15] D. K u c, E. H a d a s i k, I. S c h i n d l e , P. K a w u l o k, R. Ś l i w a, Cha ac e is ics o plas ici y and mic os uc u e o ho o ming magnesium alloys Mg Al-Zn ype. A chi es o Me allu gy and Ma e ials 58, 1, 151-156 (2013). Recei ed: 10 May 2013. B ough o you by | Technicka Uni e zi a Os a a Au hen ica ed | 158.196.184.56 Download Da e | 5/21/14 2:21 PM