Effect of Micro Solidification Crack on Mechanical Performance of Remote Laser Welded AA6063-T6 Fillet Lap Joint in Automotive Battery Tray Construction

Applied Sciences

Conghui Liu¹  Dariusz Ceglarek²  Pasquale Franciosa²  Tianzhu Sun²  Fabio Pierro² 

[1] School of Materials, The University of Manchester, Manchester M13 9PL, UK;Warwick Manufacturing Group (WMG), University of Warwick, Coventry CV4 7AL, UK;

关键词: battery tray;    remote laser welding;    micro solidification cracks;    beam oscillation;    power modulation;    joint integrity;   

DOI  :  10.3390/app11104522

来源: DOAJ

【 摘 要 】

Remote laser welding (RLW) has shown a number of benefits of joining 6xxx aluminium alloys such as high processing speed and process flexibility. However, the crack susceptibility of 6xxx aluminium alloys during RLW process is still an open problem. This paper experimentally assesses the impact of transverse micro cracks on joint strength and fatigue durability in remote laser welding of extruded AA6063-T6 fillet lap joints. Distribution and morphology of transverse micro cracks were acquired by scanning electron microscope (SEM) on cross-sections. Grain morphology in the weld zone was determined by electron backscatter diffraction (EBSD) while static tensile and dynamic fatigue tests were carried out to evaluate weld mechanical performance. Results revealed that increasing welding speed from 2 m/min to 6 m/min did not introduce additional transverse micro cracks. Additionally, welding at 2 m/min resulted in tensile strength improvement by 30% compared to 6 m/min due to the expansion of fusion zone, measured by the throat thickness, and refinement of columnar grains near fusion lines. Furthermore, the weld fatigue durability is significantly higher when fracture occurs in weld root instead of fusion zone. This can be achieved by increasing weld root angle with optimum weld fatigue durability at around 55°.

【 授权许可】

Unknown