Enhanced mechanical properties of 3D printed Zr-based BMG composite reinforced with Ta precipitates

Abstract：

3D printing technique based on selective laser melting (SLM) provides a new approach to fabricate complex bulk metallic glass (BMG) components. However, the structural relaxation and partial crystallization of the pre-formed amorphous phase in heat affect zones (HAZs) caused by repeated laser scanning deteriorate the mechanical properties, i.e., reducing plasticity and fracture toughness. Here, we attempted the preparation of Zr-based metallic glass composites reinforced with precipitation of Ta particles by SLM technique. The results show that, in a wide range of energy densities, the 3D printed BMG composites exhibit high amorphous fraction (>90 %) and good mechanical properties with fracture strength of 1.9 GPa, plastic strain of around 2.15 % and fracture toughness (Kq) of 60 MPa·m1/2, and the plastic strain is the highest values achieved in 3D printed BMGs so far. The suppression of crystallization of amorphous phase in HAZs and the precipitation of Ta particles in amorphous matrix can account for the enhancement of plasticity and fracture toughness while maintaining high strength. This work provides a hint for the preparation of toughening BMG composites by using 3D printing technique.