Columnar grain width control for SS316L via hatch spacing manipulation in laser powder bed fusion

• Main Authors: Hu, Zhiheng, Gao, Shubo, Tai, Junfei, Qu, Shuo, Ding, Junhao, Song, Xu, Fan, Zheng
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Mechanical engineering; Laser Powder Bed Fusion; Hatch Spacing
• Online Access: https://hdl.handle.net/10356/165024
• Institution: Nanyang Technological University

This study provides a quantitative way to tailor the grain structure in laser powder bed fusion (LPBF). Square-bottomed columnar grains (SCGs) were developed with a certain width roughly equal to the hatch spacing. The development of SCGs relied on different distinguishable regions, which were identified based on the differences in microstructural features between the melt-pool side and centreline. High lattice rotation accumulated at the melt-pool centreline, leading to grain boundaries forming at the centreline regions. The ultrasonic attenuation measurements and microhardness tests further validated the controllable properties. The findings indicated a novel approach to customise the material property.