Effects of thermomechanical treatments on the microstructures and mechanical properties of GTA-welded AZ31B magnesium alloy

Ya-jie Chu 1,2),Jian Chen 1),Xiao-quan Li 2),Shen-qing Wu 1),and Zong-hui Yang 2) 1) Department of Material Science and Engineering,Jiangsu Key Laboratory for Advanced Metallic Materials,South East University,Nanjing 211189,China 2) Department of Material Engineering,Nanjing Institute of Technology,Nanjing 211167,China

摘 要：Thermomechanical treatments were carried out to improve the properties of AZ31B joints prepared by gas tungsten arc welding.The microstructures of the joints were studied by optical microscopy and scanning electron microscopy with energy-dispersive spectrometry.Tensile tests and hardness tests were performed to investigate the effects of thermomechanical treatments on the mechanical properties of the joints.It is found that the thermomechanical-treated joints show superior mechanical properties against the as-welded joints,and their ultimate tensile strength can reach more than 92% of the base material.This mainly attributes to the formation of fine equiaxed grains in the fusion zone.After thermomechanical treatments the dendrites are transformed to fine spherical grains,and the dendritic segregation can be effectively eliminated.

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