摘要
振荡激光焊接工艺通过激光束的搅拌作用,能够有效促进焊接熔池的流动,改善溶质元素的分布.本文采用振荡激光焊接工艺对7075-T6铝合金进行焊接,并使用自制的Al-Mg焊材作为填充材料.结合SEM、TEM及热力学计算,系统研究了焊缝成型及组织演变规律.研究结果表明,当振荡幅度为0.8 mm时,激光束的振荡范围足以覆盖整个焊材区域,确保焊材完全熔化,而振荡频率对焊缝横截面面积的影响较小.在振荡频率为200 Hz的条件下,焊缝区的平均晶粒尺寸为17.9μm.振荡工艺促进了Y元素在熔池中的流动,增强了其溶质限制生长效应,此外搅拌作用使得焊缝组织更均匀,从而使焊接接头的抗拉强度达到343 MPa,延伸率为2.9%.热力学计算结果表明,焊缝中的析出相顺序为:L→Al_(3)Ti→Al_(13)Cr_(2)→Al_(10)RM_(2)→Mg_(2)Si→Al_(4)MgY→S_Al_(2)CuMg→Al_(4)Ca→T_AlMgZn.
Oscillating laser welding enhances the flow of the molten pool and improves the distribution of solute elements through its stirring effect.In this study,7075-T6 aluminum alloy was welded using oscillating laser welding with a self-developed Al-Mg filler material.By integrating scanning electron microscopy(SEM),transmission electron microscopy(TEM),and thermodynamic calculations,the weld formation and microstructure evolution were investigated.The results demonstrate that an oscillation amplitude of 0.8 mm ensures complete melting of the filler material,while the oscillation frequency has minimal impact on the weld cross-sectional area.At an oscillation frequency of 200 Hz,the average grain size in the fusion zone is 17.9μm.The oscillating process promotes the flow of Y in the molten pool,enhancing its solute-restricted growth effect.Furthermore,the stirring action results in a more homogeneous weld microstructure,achieving a tensile strength of 343 MPa and an elongation of 4.1%for the welded joint.Thermodynamic calculations reveal that the precipitation sequence in the weld is as follows:L→Al_(3)Ti→Al_(13)Cr_(2)→Al_(10)RM_(2)→Mg_(2)Si→Al_(4)MgY→S_Al_(2)CuMg→Al_(4)Ca→T_AlMgZn.
作者
李传胜
王雷
伍亚辉
杨祥帆
于文晶
王利忠
王洪宝
张怀强
张英波
LI Chuan-Sheng;WANG Lei;WU Ya-Hui;YANG Xiang-Fan;YU Wen-Jing;WANG Li-Zhong;WANG Hong-Bao;ZHANG Huai-Qiang;ZHANG Ying-Bo(CRRC Changchun Railway Vehicles Car Company Limited,Changchun 611435,China;School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《四川大学学报(自然科学版)》
北大核心
2025年第4期803-811,共9页
Journal of Sichuan University(Natural Science Edition)
基金
航空装备先进材料与制造技术四川省国防科技重点实验室(2023KFKT0006)
四川省重大科技专项(2023ZDZX0003)。
关键词
振荡激光焊接
7075铝合金
微观组织
力学性能
热力学计算
Oscillating laser welding
7075 aluminum alloy
Microstructure
Mechanical properties
Thermodynamic calculations
