Superplastic behavior of friction-stir welded Al-Mg-Sc-Zr alloy in ultrafine-grained condition  

搅拌摩擦焊超细晶Al-Mg-Sc-Zr合金的超塑性行为

作　　者：I.VYSOTSKIY K.KIM S.MALOPHEYEV S.MIRONOV R.KAIBYSHEV I.VYSOTSKIY;K.KIM;S.MALOPHEYEV;S.MIRONOV;R.KAIBYSHEV(Belgorod National Research University,Pobeda 85,Belgorod 308015,Russia)

机构地区：[1]Belgorod National Research University,Pobeda 85,Belgorod 308015,Russia

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第4期1083-1095,共13页中国有色金属学报（英文版）

基　　金：financially supported by the Russian Science Foundation(No.18-79-10174)。

摘　　要：The present work was undertaken to improve superplastic ductility of friction-stir welded joints of ultrafine-grained(UFG)Al-Mg-Sc-Zr alloy.In order to suppress the undesirable abnormal grain growth,which typically occurs in the heavily deformed base material,the UFG material was produced at elevated temperature.It was suggested that the new processing route could reduce dislocation density in the UFG structure and thus enhance its thermal stability.It was found,however,that the new approach resulted in a relatively high fraction of low-angle boundaries which,in turn,retarded grain-boundary sliding during subsequent superplastic tests.Therefore,despite the successful inhibition of the abnormal grain growth in the base-material zone,the superplastic deformation was still preferentially concentrated in the fully-recrystallized stir zone of the material.As a result,the maximal elongation-to-failure did not exceed 700%.研究提高搅拌摩擦焊超细晶(UFG)Al-Mg-Sc-Zr合金接头超塑性的新工艺。为了抑制严重变形基体材料中通常出现的异常晶粒长大现象,在高温下制备UFG材料。结果表明,新工艺路线可以降低UFG组织中的位错密度,从而提高其热稳定性。然而,新方法导致相对较高的小角度晶界比例,从而在随后的超塑性试验中延缓晶界滑动。因此,尽管成功抑制了基材区晶粒的异常长大,但超塑性变形仍优先集中在完全再结晶搅拌区材料中,从而导致最大断裂伸长率未超过700%。

关 键 词：aluminum alloys equal-channel angular pressing friction-stir welding ultrafine-grained materials SUPERPLASTICITY 

分 类 号：TG453.9[金属学及工艺—焊接] TG146.21[一般工业技术—材料科学与工程]