LZ91超轻双相镁锂合金激光搭接焊接接头的显微组织与力学性能  

Microstructure and Mechanical Properties of LZ91 Mg-Li Alloy Laser Welded Lap Joints

作　　者：金福帅 杨子郁 张珈硕 胥鑫 徐荣正 JIN Fushuai;YANG Ziyu;ZHANG Jiashuo;XU Xin;XU Rongzheng(School of Material Science and Engineering,Shenyang Aerospace University,Shenyang 110136,China)

机构地区：[1]沈阳航空航天大学材料科学与工程学院,沈阳110136

出　　处：《有色金属工程》2023年第3期18-22,共5页Nonferrous Metals Engineering

基　　金：辽宁省兴辽英才计划项目(XLYC2007165);沈阳航空航天大学创新创业训练计划项目(X202210143033)。

摘　　要：采用激光焊接技术对厚度为4 mm的LZ91镁锂合金板材进行搭接焊接,重点研究了激光功率的变化对接头组织与力学性能的影响。结果表明,在激光输出功率为2.3 kW,焊接速度为1 m/min,氩气流量为25 L/min,离焦量为+2 mm的工艺参数下,可以得到焊缝表面成形良好,横截面没有明显缺陷的高质量搭接接头,但在上下板搭接界面处发现了微气孔缺陷。焊缝中心组织为等轴晶,熔合线附近为柱状晶。接头的硬度(61.4 HV)比母材(52.1 HV)提高了17.9%,焊缝区显微硬度最高,母材次之,热影响区最低。拉剪测试结果显示,搭接焊接接头的抗拉伸剪切力为2 409.5 N,抗拉剪切强度达到了120.3 MPa。搭接接头断裂发生在上下板之间的搭接连接处。Laser welding technology was used for lap welding of LZ91 magnesium-lithium alloy plate with a thickness of 4 mm, focusing on the effects of the variation of laser power on the organization and mechanical properties of the joint.The results show that under the laser output power of 2.3 kW,welding speed of 1 m/min, argon flow rate of 25 L/min, the amount of defocusing +2 mm process parameters, high-quality lap joints with well-formed weld surfaces and no obvious defects in cross section can be obtained, but micro porosity defects were found at the lap interface of the upper and lower plates.Weld center organization is equiaxed crystal.Near the fusion line are columnar crystals.The hardness of the joint(61.4 HV)was 17.9% higher than that of the base material(52.1 HV),with the highest microhardness in the weld zone, followed by the base material and the heat affected zone is the lowest.The tensile shear test results show that the tensile shear resistance of the lap welded joint is 2 409.5 N and the tensile shear strength reach 120.3 MPa.The fracture of the lap joint occur at the lap joint between the upper and lower plates.

关 键 词：镁锂合金 激光焊接 搭接接头 工艺参数 显微组织 力学性能 

分 类 号：TG44[金属学及工艺—焊接]