热压对镁合金焊接接头拉伸性能的影响

摘要

The effects of hot-press on tensile properties and fracture morphology of AZ31B magnesium alloy welded joint welded by argon tungsten-arc welding were studied by tensile test,optical microscopy and scanning electron microscopy.The results show that the tensile strength and elongation of welded joint after hot-press were 200 MPa and 10%,respectively,and increased by 18% and 67% comparing with that of welded joint before hot-press.The tensile fracture of welded joint was mainly cleavage and more footmark platforms,accompanied by small amount of dimples.The fracture of hot-pressed joint showed the characteristics of quasi-cleavage fracture with plastic deformation flow lines,and the grains boundaries showed the phenomenon of sliding coordination.%通过拉伸试验机、光学显微镜、扫描电镜等研究了热压对AZ31B镁合金钨极氩弧焊焊接接头拉伸性能和断口形貌的影响。结果表明：热压后焊接接头的抗拉强度和伸长率分别可达200MPa和10%,比焊态的分别提高了18%和67%;焊态接头拉伸断口以解理断裂为主,呈现出较多的脚印状小平台,同时伴随有少量韧窝;而热压后焊接接头的断口具有平台撕裂畸变现象,可以观察到热压塑性变形流变线,晶界表现出一定的滑动协调现象。