Parametric analysis to explore the viability of cold spray additive manufacturing to print SS316L parts for biomedical application

Abstract

In the current work, high-pressure cold spray additive manufacturing (CS) is used to print SS316L samples to explore its potential as an AM technology for bio-implant applications. For comparison purposes, laser powder bed fusion (LPBF) is also used to print the samples. Porosity, microhardness, microstructure and young’s modulus analysis of the printed materials were done. Subsequently, the influence of heat treatment on the characteristics of printed samples was analyzed after being subjected to two distinct kinds of heat treating environments, viz. cooling in air and furnace. The study results validated that the samples manufactured by the CS technique were more porous and rougher than the LPBF technique. Grain structure confirmed the presence of cellular sub-grains, dendrites, and melt pool boundaries in an as-fabricated LPBF sample. In as-fabricated CS, the microstructure consists of deformed multi-crystalline grains. Improvement in microhardness after heat treatment was observed in the LPBF samples, whereas CS exhibited less value because of the reduced effect of cold working. The heat treatment of CS samples with furnace cooling resulted in microhardness and Young’s modulus comparable to that desired for the body implants. Therefore, this study opens a pathway to explore CS as a viable technique for manufacturing bio-implants with tailor-made porosity, hardness and Young’s modulus by optimizing process parameters.