Microstructures and properties of AZ31B magnesium alloy TIG welding joints

WU Xiaoming; CHEN Liyuan; JING Feng; MA Yongzhi; GUO Ruiqing

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Microstructures and properties of AZ31B magnesium alloy TIG welding joints
Vol. 48, Issue 3, Pages: 246-249(2018)
Published：2018
DOI：
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DOI：

WU Xiaoming, CHEN Liyuan, JING Feng, et al. Microstructures and properties of AZ31B magnesium alloy TIG welding joints[J]. Eletric Welding Machine2018, 48(3): 246-249. DOI：

摘要

通过拉伸、弯曲和硬度等试验以及金相显微组织分析

研究4 mm AZ31B镁合金焊接接头组织和性能。试验结果表明:4 mm拉伸试件断裂位置位于热影响区;抗拉强度满足要求;所有弯曲试件的面弯和背弯均未出现断裂

弯曲性能良好;TIG焊焊缝区晶粒相对细小

组织为α-Mg固溶体

晶界弥散分布着黑色β-Mg17Al12沉淀相

热影响区组织晶粒较母材有所长大;母材硬度高于热影响区和焊缝

接头热影响区有软化现象;从4 mm AZ31B镁合金TIG焊对接接头(去掉余高)脉动拉伸疲劳试件宏观形貌可以看出

断裂位置为热影响区。

Abstract

Microstructures and properties of 4 mm AZ31 B magnesium alloy welded joints welding by TIG were studied respe-ctively through tensile tests

bending tests

hardness tests and analysis in this paper. The tensile test results showed that

all the specimens were broken in the heat affected zone and the tensile strength satisfied the standard. The grain size of the TIG weld zone is relatively small

the organization is α-Mg solid solution

the grain boundary is dispersed with the black β-Mg17 Al12 precipitation phase

and the grain size of the heat affected zone is longer than that of the base metal. The hardness of the base metal is higher than that of the heat area and weld

there is a softening phenomenon in the joint heat affected zone. It also can be seen that the cracked position of the pulsating tensile fatigue fracture specimen of the 4 mm AZ31 B magnesium alloy TIG welding joint（removed excess weld metal） is in the heat affected zone.