AZ31B/Cu复合材料的扩散焊制备与界面显微组织分析  

Diffusion Bonding Preparation of AZ31B/Cu Composite and Analysis of Interface Microstructure

作　　者：杜双明[1] 刘刚[1] 王明静[1] 

机构地区：[1]西安科技大学,陕西西安710054

出　　处：《稀有金属材料与工程》2014年第2期475-480,共6页Rare Metal Materials and Engineering

摘　　要：采用真空扩散焊工艺,在加热温度500℃、保温时间40 min、压力2.5 MPa、真空度1.0×10-2 Pa下制备了变形镁合金AZ31B/Cu双金属复合材料,并对复合材料界面区的微观结构和力学性能进行分析,探讨了界面反应层的形成机理。结果表明:铜在镁合金一侧富集出现晶界渗透现象。镁合金/Cu界面的组织依次为:α-Mg和沿其晶界析出相Mg17(Cu,Al)12/α-Mg/(α-Mg+Mg2Cu)共晶/Cu2Mg金属间化合物/(α-Mg+Mg2Cu)共晶/Cu(Mg)固溶体。硬度在基体两侧到界面中心区域内呈台阶式增加,最高显微硬度达到3510 MPa。Cu2Mg两侧的共晶液相出现具有先后次序,晶界渗透区与Cu2Mg之间先形成Mg-Cu共晶液相,然后共晶液相中的Mg原子穿越Cu2Mg层扩散至Cu侧,在Cu2Mg与Cu(Mg)固溶体之间形成Mg-Cu共晶液相。复合材料的界面抗剪强度达到61 MPa,剪切断裂发生在界面扩散层内,断口由撕裂棱和撕裂棱两边的大小不一的解理台阶构成。AZ31B/Cu bimetallic composite was prepared by diffusion bonding process under the condition of 500 ℃, pressure of 2.5 MPa, holding time of 40 min and vacuum of 1.0× 10^-2 Pa. The microstructures and mechanical properties of the interface diffusion zone for the AZ31B/Cu bimetallic composite were analyzed, and the growing mechanism of interracial reaction layers was discussed. The results show that the grain boundary penetration is obvious due to the Cu enrichment on the side of Mg alloy. The microstructure of interface zone of AZ31B/Cu composite from Mg alloy to copper includes the grain boundary penetration layer composed of a-Mg and Mg17（CU, Al）12which was precipitated along the grain boundary of a-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 micro-hardness for bonding diffusion interface increase step by step from the base metal to the center of interface zone, and the maximal micro-hardness is 3510 MPa. The eutectic phase beside Cu2Mg does not appear at the same time, the eutectic phase is early generated at the interface of the grain boundary penetration layer and the Cu2Mg layer, and element Mg in eutectic phase diffuses to copper through the Cu2Mg layer, then eutectic phase is generated at the interface of Cu2Mg and Cu（Mg）. The average shear strength of AZ31B/Cu composite reaches 61 MPa. The fracture surface of AZ31B/Cu composite is located within its interface diffusion layer, the fracture morphology mainly consists of a tearing ridge and a cleavage plane with different sizes.

关 键 词：AZ31B CU复合材料 扩散焊 界面 显微组织 

分 类 号：TG453.9[金属学及工艺—焊接]