Structural mechanics analysis on 3D printed metal layers on a dissimilar metal base

Abstract

The demand for a wider range of properties and functionalities has led to more research and developments in the additive manufacturing industry. There has been a heightened interest in multi-material additive manufacturing of dissimilar metal alloys due to the potential of it satisfying the demand. While there is extensive research done on the additive manufacturing of SS316L and CuCrZr individually, limited research has been done on the selective laser melting of these materials in multi-material additive manufacturing.

The mechanical properties and microstructure of SS316L and CuCrZr made by SLM with different printing parameters were analysed in this project. Vickers microhardness and tensile tests were carried out to determine any correlations between the mechanical properties and printing parameters. It was found that the volumetric energy density absorbed by the material played a crucial role in ensuring complete melting of the particles and bonding between the layers, affecting the mechanical properties. However, an increase in volumetric energy density does not necessarily result in a proportionate rise in ultimate tensile strength or microhardness. When the melt pool size becomes too large, there is a non-uniform thermal distribution. This non-uniform thermal distribution caused by the increase in volumetric energy density can cause the increase in formation of defects and a decline in the ultimate tensile strength.

Remelting of the first layer can help mitigate the effects of thermal mismatch and promote better diffusion of material particles. However, remelting can increase intermetallic concentration, resulting in a more brittle material.