摘要
采用光纤激光器焊接3 mm厚AZ31B镁合金对接接头,借助光学显微镜、扫描电子显微镜、拉伸实验机和显微硬度计对接头焊缝成形、微观组织及力学性能进行研究。结果表明,镁合金光纤激光焊接焊缝宽度窄且表面成形良好,焊接末段上表面和背部分别出现微量下塌和上凹。焊缝区为细小的等轴晶,热影响区组织相对母材发生粗化;沿焊接方向,焊缝区的晶粒尺寸逐渐增大。焊接接头热影响区硬度最低,拉伸试样的抗拉强度和延伸率可达母材的95.1%和89.3%,此时在热影响区以韧脆混合模式发生断裂。
The 3 mm thick AZ31B magnesium alloy butt joints are carried out by fiber laser welding. Weld morphology, microstructural and mechanical characteristics of welded joints are investigated by means of optical microscope, scanning electron microscopy （SEM）, tensile test machine and Vickers hardness tester. The results show that the weld zone width is narrow and weld appearances are smooth, but at the end of weld, the top surface collapse and back surface appear concave a little. The weld zone is characterized by fine equiaxed, and heat affected zone microstructures coarsen compared with the basemetal. The weld zone grain size increases according to the weld direction. The hardness in heat affected zone of welded joints is minimum, so the tensile samples without pore and crack defect rupture with ductile-brittle mixed mode in the heat affected zone. The ultimate tensile strength and elongation of is up to 95.1% and 89.3% of the basemetal.
出处
《激光与光电子学进展》
CSCD
北大核心
2015年第9期229-233,共5页
Laser & Optoelectronics Progress
基金
吉林省博士后科研启动基金(801130030414)
吉林大学青年教师创新项目(450060501279)
关键词
激光技术
光纤激光焊接
镁合金
焊缝成形
显微组织
拉伸性能
laser technique
fiber laser welding
magnesium alloy
weld morphology
microstructure
tensile properties
