Additive Manufacturing of CoCrNi Medium Entropy Alloy

Sri Bala Aditya Malladi, Zhuoer Chen, Shen Guo, Lars Nyborg

Chalmers University of Technology, Sweden

The main aim of this study is to understand the printability and solidification behavior of the High Entropy Alloys using laser powder bed fusion (L-PBF). High entropy alloys (HEAs) are a novel class of alloys which contain multiple principal elements in near equiatomic proportions. The unprecedented compositional complexity has reportedly enabled HEAs to perform better than conventional alloys in various situations. Manufacturing HEAs using additive manufacturing techniques such as L-PBF helps in reducing the phase segregation and preventing the formation of detrimental phases, owing to the very high solidification rates. In this study, pre-alloyed gas atomized powders of CoCrNi, medium entropy alloy were investigated. Influence of various printing parameters on the densification and its resulting microstructure was observed. CoCrNi showed excellent printability. The printed parts were then characterized using X-ray diffraction and EBSD. Microstructural examination on the printed parts shows the epitaxial growth of grains in the build direction with a cellular solidification structure. 

Keywords: Laser powder bed fusion, Medium Entropy Alloy, Solidification structure, EBSD