焊后热处理对AZ80镁合金电阻点焊接头组织及性能的影响  

Effect of Post-Weld Heat Treatment on Microstructure and Properties of Resistance Spot Welding Joint of AZ80 Magnesium Alloy

作　　者：金明[1] 

机构地区：[1]重庆工业职业技术学院,重庆401120

出　　处：《热加工工艺》2017年第13期217-220,224,共5页Hot Working Technology

摘　　要：采用电阻点焊实现了AZ80镁合金的搭接,并对点焊接头试样进行了焊后热处理。使用扫描电镜、能谱分析和拉剪试验研究了焊后热处理对点焊接头微观组织及力学性能的影响。结果表明,电阻点焊接头熔合区和热影响区均主要由α-Mg和沿晶界呈连续分布的网状Mg_(17)Al_(12)组成。在拉剪载荷下,裂纹主要沿接头热影响区扩展,接头发生了熔核拔出失效,接头强度较低。经400℃×0.5 h焊后热处理,接头中Mg_(17)Al_(12)相部分重溶进基体,网状Mg_(17)Al_(12)相明显减少。热处理后接头在拉剪试验中沿母材发生失效,接头强度提高。The lap joint of AZ80 magnesium alloy was welded by resistance spot welding and the post weld heat treatment was carried out. The effect of post weld heat treatment on the microstructure and mechanical properties of the spot welded joints were investigated by scanning electron microscope, energy spectrum analysis and tensile-shear test. The results show that the fusion zone and heat affected zone of the resistance spot welding joint are mainly composed of α-Mg and reticular Mg17Al12 continuously distributing along the grain boundaries. The crack mainly extends along the heat affected zone of the joint in the condition of tensile shear load. The nugget pulling out failure occurs in the joint and the joint strength is low. After heat treatment at 400 ℃ for 0.5 h, the partial Mg17Al12 phase of the joint is redissolved into the matrix, and the reticular Mg17Al12 phase is obviously reduced. As a result, the failure of joint occurs along the base metal in the tensile shear test, and joint strength is improved after heat treatment.

关 键 词：AZ80镁合金 电阻点焊 焊后热处理 MG17AL12 

分 类 号：TG453.9[金属学及工艺—焊接] TG166.4