Insight into micro-cracking in 3D-printed Fe-based BMGs by selective laser melting

Experiments combined with finite element method (FEM) were applied to investigate the origin of micro-cracking in 3D printed a Fe-based bulk metallic glass (Fe_43.7Co_7.3Cr_14.7Mo_12.6C_15.5B_4.3Y_1.9) by selective laser melting (SLM). It is revealed that thermal stress concentration around micro-pores is the main cause for the formation of micro-cracks in the 3D-printed Fe-based BMG. Both the location and size of micro-pores play important roles in the generation of micro-cracks: Thermal stress is more serious at the edge between molten pool and heat affect zone with respect to other regions, while thermal stress concentration is increased with the decrease of pore size. Based on FEM simulations and experimental results, a critical dimension of 30 μm of pores was induced for the generation of micro-cracks in the present 3D printed Fe-based BMG components.