Influence of hatch distance on processing, microstructure and mechanical properties of AlMgScZr alloy fabricated by laser powder bed fusion

作者：Li, Xiang; Liu, Yunzhong^*; Zhou, Zhiguang

来源：Journal of Manufacturing Processes, 2022, 81: 78-91.

DOI：10.1016/j.jmapro.2022.06.036

• Laser powder bed fusion
• AlMgScZr alloy
• Hatch distance
• Densification
• Microstructure
• Mechanical properties

Laser powder bed fusion (LPBF) has significant requirements for the optimization of laser process parameters. In this study, AlMgScZr alloy was fabricated by LPBF using different hatch distances. The influence of hatch distance on densification behavior, melting mode, crystallographic orientation, misorientation evolution and tensile properties was in-depth investigated. Results indicated that the densification was enhanced as the hatch distance decreased, almost full-dense samples (>99.50 %) were obtained with a small hatch distance (i.e. 60 mu m). The formation mechanisms of pores and densification behavior were discussed. Increasing the hatch distance can gradually decrease the grain size. Meanwhile, the influence of hatch distance on melting mode was distinct, the melting mode transformed from keyhole to conduction mode with the increase of hatch distance. Exceptional tensile properties above 540 MPa combined with elongations of 23.00 % were achieved and the underlying strengthening mechanisms are elucidated. These results are of great significance for not only understanding the influence of hatch distance on processing, microstructure and mechanical properties of LPBF-fabricated AlMgScZr alloy, but also for facilitating the future development of high-performance AlMgScZr alloy in aerospace, automotive and other fields.