Improving mechanical properties of quasi-continuous-wave laser beam welded 7075 aluminum alloy through microstructural refinement and homogenization of the fusion zone. (September 2022)

• Record Type: Journal Article
• Authors: Luo, Guoyun; Cheng, Manping; Liu, Chenghuan; Li, Simeng; Wang, Xiaogang; Song, Lijun
• Is Part Of: Optics & laser technology. Volume 153(2022)
• Publication Date: 2022-09
• Subjects: Laser beam welding -- Quasi-continuous-wave laser -- Aluminum alloy -- Microstructure -- Mechanical properties; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2022.108221
• Languages: English
• ISSNs: 0030-3992

Abstract

Graphical abstract: Highlights: Homogeneous refined equiaxed grains are obtained in the dense fusion zone. The strengthened and homogenized fusion zone reduces strain concentration. 78.56% strength efficiency accompanied with 26.39% elongation efficiency are achieved. Abstract: Laser beam welding of aluminum alloy is challenged by poor mechanical properties of weld joint. Here we employ a quasi-continuous-wave laser beam welding to join 7075-T6 aluminum alloy sheets. High cooling rate, unconstrained multi-directional solidification and high overlapping factor of the quasi-continuous-wave laser beam welding produce a dense fusion zone with homogeneous, refined, and equiaxed grain and dendrite structures. The tailored fusion microstructure is beneficial for improved yield strengthen, enhanced plastic deformation and relieved strain concentration of the weld. A 78.56% strength efficiency and a 26.39% elongation efficiency are achieved. The results demonstrate that the microstructural refinement and homogenization of the fusion zone are effective to improve mechanical properties of weld joint.