Innovative liquid metal strategy for real-time thermal control in additive manufacturing

Abstract

Metal additive manufacturing (AM) involves rapid cycles of melting and solidification, often resulting in significant thermal stress variations, microcrack formation, and compromised structural integrity, especially for complex structures. Effective strategies are crucial for regulating temperature and stress distribution during laser-based metal AM processes; however, traditional thermal management approaches suffer from limitations in action area and response speed. In this study, the novel Liquid Metal-Assisted Additive Manufacturing (LMAAM) process is developed to enhance real-time temperature and stress control during deposition. This is the first known attempt to utilize liquid tin as an auxiliary thermal management material for AM. Numerical simulations and experimental analysis are performed to determine the relationship between LMAAM process conditions and resultant material microstructural properties. The results show that compared to AM without active thermal management, the incorporation of liquid tin yields an approximate 20 % increase in the cooling rate, a roughly 30 % reduction in residual tensile stress, a decrease in part grain size, and a roughly 30 % enhancement in microhardness. LMAAM technology opens up new possibilities for metal AM of highly reliable and intricate structures like multi-chambers, multi-channels, and deep blind holes.