Ti/Al异种金属微电阻点焊接头力学性能及显微组织  

Mechanical Properties and Microstructure of Ti/Al Joint of Micro-resistance Welding

作　　者：高原 陈玉华 占字林 王善林 GAO Yuan;CHEN Yu-hua;ZHAN Zi-lin;WANG Shan-lin(National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学轻合金加工科学与技术国防重点学科实验室,南昌330063

出　　处：《精密成形工程》2018年第4期90-95,共6页Journal of Netshape Forming Engineering

基　　金：江西省优势科技创新团队建设专项计划项目(20171BCB24007);国家自然科学基金(51265042)

摘　　要：目的对0.2 mm厚的TC4和2A12薄板进行微电阻点焊研究,并确定最佳工艺参数。方法通过测量接头剪切强度以及观察接头横截面形貌,研究工艺参数对接头拉剪力的影响,采用扫描电子显微镜(SEM)对点焊接头的连接特征及断裂行为进行深入研究,借助金相显微镜对接头微观组织进行分析。结果焊接时间对接头的抗拉剪力没有显著影响,当焊接电流为4.2 k A,电极压力为110 N,焊接时间为10 ms时,取得最大剪切强度125.82 N。接头有两种断裂方式,分别为沿熔核中心断裂和纽扣状断裂。沿熔核中心断裂的断口呈现脆性断裂的特征,钮扣状断裂的断口熔核中心处呈韧性断裂特征,其热影响区呈脆性断裂特征。结论实现了Ti/Al薄板的微电阻点焊,并通过改变工艺参数获得良好的剪切性能。观察焊缝的显微组织发现,远离熔核中心、靠近铝母材侧的区域,由于铝侧母材散热较好,组织为等轴晶以及细小的柱状晶,晶粒较小。靠近熔核中心的区域为组织较为粗大的柱状枝晶。The paper aims to research micro-resistance welding point of TC4 and 2A12 thin plate with a the thickness of 0.2 mm and determine the optimum process parameters. By measuring the shear strength of the joint and observing the shape of the cross section of the joint, influences of process parameters on the tensile shear force of the joint were studied. The connection characteristics and fracture behaviors of spot welding joints were studied with scanning electron microscope（SEM）. The welding time had no significant influence on the tensile shear force of the joint. When the welding current was 4.2 kA and the electrode pressure 110 N welding time was 10 ms, the maximum shear strength was 125.82 N. There were two fracture modes in the joint： central fracture and button fracture. The former was characterized by brittle fracture and the core of the latter was characterized by ductile fracture and the characteristic of brittle fracture in the heat affected zone. The micro resistance spot welding of Ti/Al sheet is realized, and the good shear performance is obtained by changing the process parameters. Due to the better heat dissipation of the aluminum side, the tissues far away from the core of the nugget are equiaxed and fine columnar crystals with smaller grain size. The region near the core of the nugget is a larger columnar dendrite.

关 键 词：异种金属 微电阻点焊 力学性能 

分 类 号：TG206[金属学及工艺—铸造]