Effect of laser additive manufacturing on microstructure evolution of inoculated Zr47.5Cu45.5Al5CO2 bulk metallic glass matrix composites

Abstract

Bulk metallic glass matrix composites are advocated to be material of future owing to their superior strength, hardness and elastic strain limit. However, they possess poor toughness which makes them unusable in any structural engineering application. Inoculation has been used as an effective means to overcome this problem. Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composites (BMGMC) inoculated with ZrC have shown considerable refinement in microstructure owing to heterogeneous nucleation. Efforts have also been made to exploit modern laser-based metal additive manufacturing to fabricate BMGMC parts in one step. However, the effect of laser treatment on inoculated material is unknown. In this study, an effort has been made to apply laser based additive manufacturing on untreated and inoculated BMGMC samples. It is observed that laser treatment not only refined the microstructure but resulted in change of size, morphology and dispersion of CuZr B2 phase in base metal, heat affected zone and fusion zone. This effect is documented with back scattered electron imaging. This provides a basis for further research to quantify this phenomenon and full-scale part development.