Structural and Mechanical Characteristics of Cu₅₀Zr₄₃Al₇ Bulk Metallic Glass Fabricated by Selective Laser Melting

In this work, the structural and mechanical characteristics of Cu₅₀Zr₄₃Al₇ bulk metallic glass (BMG) fabricated by selective laser melting (SLM) are studied and the impacts from the SLM process are clarified. Cu₅₀Zr₄₃Al₇ alloy specimens were manufactured by the SLM method from corresponding gas-atomized amorphous powders. The as-built specimens were examined in terms of phase structure, morphologies, thermal properties and mechanical behavior. The x-ray diffraction and differential scanning calorimetry results showed that structural relaxation and partial crystallization co-exist in the as-fabricated Cu₅₀Zr₄₃Al₇ glassy samples. The nano- and micro- hardness and the elastic modulus of the SLM-fabricated Cu₅₀Zr₄₃Al₇ BMG were higher than CuZrAl ternary BMGs with similar compositions prepared by conventional mold casting, which can be attributed to the structural relaxation in the former sample. However, the macro compressive strength of the SLM-fabricated Cu₅₀Zr₄₃Al₇ BMG was only 1044 MPa mainly due to its porosity. This work suggests that the SLM process induced changes in structural and mechanical properties are significant and cannot be neglected in the fabrication of BMGs.