ZM5镁合金TIG焊接接头组织与力学性能  

Microstructure and Mechanical Properties of TIG Weld Joint of ZM5 Magnesium Alloy

作　　者：秦仁耀[1] 孙兵兵[1] 肇恒跃 郭绍庆[1] 唐思熠[1] 张学军[1] 

机构地区：[1]北京航空材料研究院3D打印研究与工程技术中心,北京100095 [2]沈阳飞机工业集团有限公司驻军代表室,沈阳110034

出　　处：《材料工程》2016年第6期92-97,共6页Journal of Materials Engineering

摘　　要：采用TIG焊对ZM5镁合金进行焊接,利用光学显微镜、显微硬度仪和拉伸试验机对ZM5镁合金接头的组织特征和力学性能进行研究。结果表明:ZM5合金TIG焊接接头是由热影响区、部分重熔区和焊缝组成。热影响区组织是由初生α-Mg相基体和主要分布在晶界上的α-Mg+β-Mg17Al12共晶相组成;部分重熔区中共晶相不仅大量析出在晶界上,在晶内也呈现出较均匀的弥散析出,而且其β-Mg17Al12相出现显著长大;焊缝组织则是典型的树枝晶形貌,枝晶为初生α-Mg相,枝晶间是α+β共晶相。组织形貌的差异导致接头各区域有着不同的显微硬度,也使得接头的抗拉强度和塑性都低于母材。The ZM5 magnesium alloy plates were welded by TIG welding method.The microstructural characteristics and mechanical properties of ZM5 magnesium alloy joint were studied by optical microscopy,microhardness and tensile testers.The results show that the TIG weld joint of ZM5 magnesium alloy is composed of heat affected zone,partially melted zone and weld metal.The heat affected zone is consisted of primaryα-Mg phase and eutectic phase that is composed of eutecticα-Mg and eutecticβ-Mg17Al12 phase and mainly precipitated at grain boundaries.In the partially melted zone,the eutectic phase is not only increasingly precipitated at grain boundaries,but also dispersed in grains,and the growth of theβ-Mg17Al12 phase is obviously observed.The microstructure in the weld is the typical dendritic morphology.The dendrites are considered as primaryα-Mg phase,and the interdendritic regions areα+βeutectic phase.The difference in the microstructure of the heat affected zone,partially melted zone and weld results in their various microhardness values,and leads to the smaller tensile strength and ductility in the ZM5 alloy weld joint than parent metal.

关 键 词：镁合金 TIG焊 显微组织 力学性能 

分 类 号：TG407[金属学及工艺—焊接]