AZ31B/Cu在不同加压方式下的扩散连接  

Diffusion Bonding of AZ31B/Cu under Different Loading Methods

作　　者：张永琴[1] 杜双明[1] 胡结[1] 

机构地区：[1]西安科技大学材料科学与工程学院,陕西西安710054

出　　处：《热加工工艺》2017年第21期31-34,共4页Hot Working Technology

摘　　要：在加热温度520℃,保温时间20 min,分别采用间歇性梯度加压、梯度加压和恒定加压对AZ31B/Cu进行扩散连接,通过扫描电镜和能谱仪分析焊接接头的显微组织和元素分布。结果表明,采用三种加压方式得到的AZ31B/Cu接头均由焊缝区及镁基体晶界渗透区构成,其中焊缝区依次由α-Cu、Cu_2Mg、(Cu+Cu_2Mg)共晶、(Mg+Mg_2Cu)共晶、α-Mg组成,镁基体晶界渗透区由α-Mg和沿其晶界分布的Mg_(17)(Cu,Al)_(12)、(λ_1+Mg_2Cu+Mg)共晶组成。加压方式对焊缝区的宽度和α-Mg的晶粒尺寸及形态影响较大,间歇性梯度加压的焊缝区宽度最大,达1.97mm,α-Mg呈粗大的柱状晶和胞状晶;梯度加压时焊缝区宽度较小,α-Mg晶粒尺寸减小;恒压加压时焊缝区宽度最小,α-Mg呈等轴晶。The diffusion brazing tests of AZ31B and Cu were carried out under intermittent gradient pressure, gradient pressure and constant pressure at 500℃ for 20 min, and the microstructure and element distribution of the welded joints were analyzed by SEM and EDS. The results show that the AZ31B/Cu joints under above three loading methods consist of weld zone and magnesium matrix＇s grain boundary penetration zone.The microstructure of the weld zone is composed of α-Cu, Cu2Mg, （Cu＋Cu2Mg） eutectic structure, （Mg＋Mg2Cu） eutectic structure and α-Mg, and the microstructure of the magnesium matrix＇s grain boundary penetration zone is composed of α-Mg and Mg17（Cu, A1）12, （λl＋Mg2Cu＋Mg） eutectic phases which are distributed along the grain boundary. The loading methods mainly affect the width of weld zone, grain size and form of α-Mg. Under intermittent gradient pressure, the width of weld zone is the biggest, which can reach up to 1.97 ram, and the α-Mg presents coarse columnar crystal and cellular crystal. Under gradient pressure, the width of weld zone and the size of α-Mg decrease. When the pressure is constant, the width of weld zone is the smallest and α-Mg presents equiaxed grain.

关 键 词：扩散钎焊 镁/铜异种金属 加压方式 显微组织 

分 类 号：TG454[金属学及工艺—焊接]