超声冲击工艺对MB8镁合金对接接头表面质量的影响  

Effect of ultrasonic impact treatment on surface quality of MB8 magnesium alloy butt joint

作　　者：丁江灏 何柏林 DING Jianghao;HE Bolin(School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学材料科学与工程学院,江西南昌330013

出　　处：《兵器材料科学与工程》2018年第4期92-96,共5页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(51365014);江西省工业支撑重点项目(20161BBE50072)

摘　　要：为提高焊接接头的表面质量,采用超声冲击方法对MB8镁合金对接接头焊趾处进行冲击处理,对原始焊态及不同冲击工艺参数下的焊趾表面质量进行对比测试及分析。结果表明:冲击后焊接接头焊趾处过渡半径增大,母材与焊缝过渡趋于平缓;焊趾表面组织得到明显细化,细化程度随冲击工艺参数的变化而变化;冲击后焊趾处由焊态的拉应力状态转变为压应力状态,表面显微硬度大幅提高;在电流为2.0 A、时间为3 min冲击工艺下,焊趾处X方向的残余压应力最大,为68.0 MPa,表面显微硬度最高,为170.4HV;接头表面质量取决于冲击时间、冲击电流两个工艺参数,但并不是所有表面质量指标都与超声冲击参数正相关或线性相关。To improve the surface quality of welded joints,the weld toe of MB8 magnesium alloy butt joint was treated by ultrasonic impact treatment（UIT）method. The surface quality of the welded toes and the treated toes with different UIT parameters was tested and analyzed. The results show that the weld edge transition arc radius r is increased after UIT,and the transition from the base metal to the weld becomes smooth. The surface microstructures of weld toe are refined,and the refined degree changes with the UIT parameters. The tensile stress state in the weld toe changes to compressive stress state,the surface micro-hardness is greatly increased. The residual compressive stress along X is the maximum（68.0 MPa）and the micro-hardness is also the highest（170.4 HV）when the UIT current and the time is 2.0 A and 3 min,respectively. Surface quality of the joint depends on the impact time and impact current,but not all surface quality indexes are positively correlated or linearly related to the impact parameter.

关 键 词：超声冲击工艺 MB8镁合金 对接接头 表面质量 

分 类 号：TG663[金属学及工艺—金属切削加工及机床] TG457.1