(西安科技大学 材料科学与工程学院，西安 710054)
摘 要: 采用过渡液相扩散焊技术对镁合金AZ31B和Cu异种金属进行焊接，利用扫描电镜(SEM)、显微硬度测试及X射线衍射(XRD)对AZ31B/Cu接头界面附近的显微组织及性能进行研究。结果表明，在500 ℃、40 min、2.5 MPa条件下，AZ31B/Cu接头形成了宽度约为450 μm的扩散区。AZ31B/Cu材料接头的显微组织依次为α-Mg和沿其晶界析出相Mg17(Cu, Al)12组成的晶界渗透层/(α-Mg+Mg2Cu)共晶层/Cu2Mg金属间化合物层/(α-Mg+Mg2Cu)共晶层/Cu(Mg)固溶体。随着保温时间的延长，界面区宽度增加，其中Cu2Mg两侧的共晶组织区的增加更为显著。界面区的显微硬度明显高于镁合金和铜基体的显微硬度，界面区明显存在4个不同的硬度分布区；随着保温时间的延长，界面区的显微硬度提高。
关键字: AZ31B/Cu 异种金属；过渡液相扩散焊；显微组织；性能
（College of Materials Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, China）
Abstract:Magnesium alloy AZ31B and Cu dissimilar metals were bonded by the transient liquid-phase diffusion bonding(TLP) process. The microstructures and properties of AZ31B/Cu TLP bonded joint were researched by SEM, micro-hardness test and XRD. The results show that under the condition of 500 ℃, 40 min and 2.5 MPa, the diffusion interface zone with a width of about 450 μm forms in TLP bonded joint of AZ31B /Cu. The microstructures of AZ31B/ Cu TLP bonded joint include the grain boundary penetration layer composed of α-Mg and Mg17(Cu, Al)12 precipitated along the grain boundary of α-Mg solid solution, eutectic of α-Mg and Mg2Cu, intermetallic compound Cu2Mg,eutectic of α-Mg and Mg2Cu, and Cu(Mg) solid solution, respectively. The interfacial width increases with increasing the holding time, and the width of eutectic beside Cu2Mg layer in interface zone increases obviously. The micro-hardness of the interface zone is much higher than that of magnesium alloy and copper, and there are obvious four hardness distribution areas. The microhardness of the interface increases with increasing the holding time.
Key words: AZ31B/Cu dissimilar metals; transient liquid-phase bonding; microstructure; properties
