搅拌针偏移对7075铝合金-AZ31镁合金接头组织及性能的影响  

Effect of the Pin Offsetting on Microstructures and Mechanical Properties of FSW Joints of 7075 Al Alloy-AZ31B Mg Alloy

作　　者：康举[1] 付瑞东[2] 栾国红[1] 何淼[1] 

机构地区：[1]北京航空制造工程研究所,北京100024 [2]燕山大学,河北秦皇岛066004

出　　处：《稀有金属材料与工程》2011年第S2期294-299,共6页Rare Metal Materials and Engineering

基　　金：航空科学重点基金资助项目(2009ZE25007)

摘　　要：通过将搅拌针向铝侧偏移0.3mm,对4mm厚的7075铝合金和AZ31B镁合金进行搅拌摩擦焊接,研究搅拌针偏移对镁铝合金焊接接头组织和性能的影响。组织分析表明:焊核区晶粒明显细化,呈现出片层状、条带状及旋涡状结构。XRD及EDS分析表明:与将搅拌针置于中心相比较,向铝侧偏移0.3mm所得接头中形成的Al12Mg17金属间化合物数量减少,但出现了Al3Mg2相。由于金属间化合物在接头热机械影响区附近大量出现,导致了该区域的硬度提高,但也成为接头的薄弱区,断裂发生于此。Friction stir welded(FSW) of 4 mm thick 7075 Al alloy and AZ31 Mg alloy plates were investigated by offsetting the pin to the Al alloy side by 0.3 mm.The aim is to investigate the effect of the tool offsetting on the microstructures and mechanical properties of FSW Mg-Al alloys joint.The results of microstructure observation show that the grains are obviously refined after FSW.The lamellas,layers and vortexes structures are presented in nugget zone(NZ).The results of XRD and EDS reveal that the quantities of Al12Mg17 intermetalic compounds are less in the NZ than that with the pin set in the center of the seam.However,Al3Mg2 phases are formed during the FSW.The hardness value increases with increasing the amount of intermetallics in the themo-mechanical affected zone(TMAZ).But the TMAZ also becomes a weak zone,and fracture occurs here during tensile test.

关 键 词：搅拌摩擦焊 7075铝合金 AZ31B镁合金 微观组织 力学性能 

分 类 号：TG407[金属学及工艺—焊接]