AA6060/AZ31复合棒材含Zn界面层显微结构与力学性能

Microstructure and Mechanical Properties of the Interface Between Co-extrusion of AA6060/AZ31 Bar with a Zn Layer

采用正向等温挤压将AA6060铝合金和AZ31镁合金制成包覆棒材,并利用XRD、OM、SEM、EDS、显微硬度仪等对加Zn层铝镁复合棒材的显微组织与力学性能进行研究。结果表明,在360℃的挤压温度下,Al/Zn/Mg界面结合良好,未见明显缺陷;Zn的加入有效减少或避免Al-Mg金属间化合物的形成,在界面处发生元素扩散,冶金反应生成Mg-Zn共晶相MgZn、MgZn、MgZn;对比Al/Mg复合,Zn促进了AZ31晶粒细化,小于5μm晶粒增加3.91%;界面处Mg-Zn共晶相明显提高了显微硬度值,可达163.1 HV,比Al/Mg界面高30 HV左右,且Al/Zn/Mg/界面剪切强度提升30.74%。

The AA6060 aluminum alloy and AZ31 magnesium alloy are prepared of coated bar by the forward isothermal extrusion,and the microstructure and mechanical properties of the Zn layer aluminum and magnesium composite bar are characterized by XRD,OM,SEM,EDS,micro hardness meter,etc.The results showed that at the extrusion temperature of 360°C,the Al/Zn/Mg interface was well bound and no obvious defects were found.The addition of Zn effectively reduced or avoided the formation of Al-Mg intermetallic compounds,and the diffusion of elements occurred in the interface to generate Mg-Zn eutectic phases MgZn,MgZnand MgZnthrough metallurgical reactions.Compared to Al/Mg composite,Zn promoted the AZ31 grain refinement,and the grains of less than 5μm increased by 3.91%.The Mg-Zn eutectic phase at the interface significantly increased the microhardness value up to 163.1 HV,which was about 30 HV higher than that of the Al/Mg interface,and the sheer intensity of the Al/Zn/Mg interface was enhanced by 30.74%.