Micro-mechanical properties and corrosion resistance of Zr₅₅Cu₃₀Al₁₀Ni₅ bulk metallic glass fabricated by spark plasma sintering

Bulk Zr₅₅Cu₃₀Al₁₀Ni₅ metallic glasses were fabricated by spark plasma sintering (SPS) of gas-atomized alloy powders and their micro-mechanical and electrochemical characteristics were investigated. The XRD and DSC results showed the sintered samples were nearly fully amorphous when sintering temperature was below material's glass transition temperature (T_g). However, partial crystallization occurred when the sintering temperature was increased above T_g. Nanoindentation test results showed that micro-mechanical characteristics of the sintered samples improved with increasing sintering temperature. The sample sintered above T_g (at 703 K) exhibited the highest hardness, elastic modulus, and fracture toughness among all the ones sintered at various temperatures, owning to the formation of thermodynamically stable intermetallic phases and annihilation of free volumes during the sintering process. Electrochemical performance of the sintered sample was also found enhanced with increasing sintering temperature. However, when the sintering temperature was above T_g, the electrochemical performance of the sintered sample was significantly weakened due to the formation of crystalline phases. The sample sintered just below T_g (at 683 K) was found to have the best thermal, micro-mechanical, and electrochemical characteristics among all the ones sintered.