Material characterization, thermal analysis, and mechanical performance of a laser-polished Ti alloy prepared by selective laser melting

• Main Authors: Li, Yu-Hang, Wang, Bing, Ma, Cheng-Peng, Fang, Zhi-Hao, Chen, Long-Fei, Guan, Ying-Chun, Yang, Shou-Feng
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2019
• Subjects: Engineering::Electrical and electronic engineering; Laser Polishing; Additive Manufacturing
• Online Access: https://hdl.handle.net/10356/86024; http://hdl.handle.net/10220/49252
• Institution: Nanyang Technological University

The laser polishing technique offers an adaptable, accurate, and environmentally friendly solution to enhance the surface quality of additive manufactured metallic components. Recent work has shown that the surface roughness of laser additive manufactured metallic alloys can be significantly reduced via the laser polishing method. This paper examines the mechanical performances of a laser polished surface fabricated by selective laser melting (SLM). Compared with the original SLM surface, systematic measurements revealed that the surface roughness of the laser polished surface can be effectively reduced from 6.53 μm to 0.32 μm, while the microhardness and wear resistance increased by 25% and 39%, respectively. Through a thermal history analysis of the laser polishing process using the finite element model, new martensitic phase formation in the laser polished layer is carefully explained, which reveals significant effects on residual stress, strength, and fatigue. These findings establish foundational data to predict the mechanical performance of laser polished metallic components fabricated by additive manufacturing methods, and pave the way for functional surface design with practical application via the laser process.