气氛对AZ31B镁合金扩散连接接头性能的影响

Influence of Furnace Atmosphere on Properties of the Diffusion Bonding Joints of AZ31B Magnesium Alloy

针对AZ31B镁合金扩散连接中的气氛保护难题,利用VDW-15型扩散焊设备对厚度为1.0mm的AZ31B镁合金薄板进行了在不同连接气氛条件下的扩散连接。分析了不同气氛下试样的表面状态,对连接接头进行了剪切强度、显微硬度等力学性能测试,利用金相显微镜、扫描电镜对不同气氛下的扩散连接接头显微组织、断口形貌进行了分析,试验结果表明,在扩散连接过程中采用抽真空至4.0×10-3Pa,再回充高纯氩气保护的方法得到了性能较好的接头,试样表面光洁,剪切强度为39.5MPa,断口分析表明其为脆性断裂。

In order to solve the problem of furnace atmosphere on diffusion bonding of AZ31B magnesium alloy, the diffusion bonding experiments for AZ31B magnesium alloy with the thickness of 1.0mm under different atmosphere conditions were carried out by using VDW-15 diffusion bonding machine. The sample surfaces under different atmospheres were analyzed. And then the mechanical properties of the joints such as shear strength and micro hardness were tested. After that the microscopic structure and fractography of those joints were analyzed by the metallurgical microscope and scanning electron microscopy. The results show that if the degree of vacuum is up to 4.0×10^-3 Pa, and then high purity argon is charged into, the best joints with the clean surface, and the shear strength of the joint is up to 39.5MPa can be get. And the fracture morphology appears brittle features.