2A12/AZ31B异质合金超声振动辅助搅拌摩擦焊核区晶粒组织  

Grain structure in ultrasonic vibration assisted friction stir weld nugget zones of 2A12/AZ31B dissimilar alloys

作　　者：井瑞 谭茂举 武传松[1] 石磊[1] JING Rui;TAN Maoju;WU Chuansong;SHI Lei(Key Laboratory for Liquid-Solid Structural Evolutionand Processing of Materials(Ministry of Education),Shandong University,Jinan 250061,China)

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《材料工程》2023年第12期75-83,共9页Journal of Materials Engineering

基　　金：国家自然科学基金项目(52035005)。

摘　　要：开展了2A12/AZ31B异种材料搅拌摩擦焊(FSW)和超声振动辅助搅拌摩擦焊(UVaFSW)的对比工艺实验,对焊核区不同部位的晶粒组织加以表征,分析超声振动对晶粒组织演变的影响。结果表明:相比于母材,焊核区2A12铝侧与AZ31B镁侧的晶粒尺寸都得到了明显的细化。2A12铝侧焊核区晶粒动态再结晶的方式为连续动态再结晶(CDRX)与几何动态再结晶(GDRX)机制的共同作用。AZ31B镁侧焊核区晶粒动态再结晶的方式为CDRX,GDRX和非连续动态再结晶(DDRX)机制的共同作用。施加超声振动能够促进晶粒的再结晶程度,尤其是在铝侧的中下部和镁侧的底部。织构演变结果表明:施加超声振动,铝侧焊核区材料的应变增加,说明超声振动能够促进焊核区的材料流动;镁侧不同区域的织构强度都有所降低,这是因为施加超声时镁合金晶粒发生了更加完全的再结晶行为,从而减弱了晶粒的取向性。The comparative experiments of 2A12/AZ31B dissimilar materials friction stir welding(FSW)and ultrasonic vibration assisted FSW(UVaFSW)were carried out.The grain structures of different parts in the weld nugget zone were characterized,and the influence of ultrasonic vibration on the grain structure evolution was analyzed.The results show that compared with the base materials,the grain sizes in the weld nugget zone(WNZ)of 2A12/AZ31B joints are obviously refined.The mode of dynamic recrystallization of grains in 2A12 Al side WNZ is the combined action of continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX)mechanisms.The dynamic recrystallization of grains in AZ31B Mg side WNZ is the combined action of CDRX,GDRX and discontinuous dynamic recrystallization(DDRX)mechanisms.Applying ultrasonic vibration can promote the recrystallization degree of grains,especially in the middle and lower parts of Al side and the bottom of Mg side.The texture evolution results show that the strain of the material in Al side WNZ increases when ultrasonic vibration is applied,which indicates that ultrasonic vibration can promote the material flow in the WNZ.The texture strength of different areas on the Mg side decreases,which is due to the more complete recrystallization behavior of magnesium alloy grains when ultrasonic is applied,thus weakening the grain orientation.

关 键 词：搅拌摩擦焊 超声振动 2A12 AZ31B 晶粒组织 焊核区 

分 类 号：TG44[金属学及工艺—焊接]