Mechanical and tribological properties of Zr–Cu–Ni–Al bulk metallic glasses with dual-phase structure

The effect of Fe addition on the structure, mechanical and wear properties of Zr–Cu–Ni–Al bulk metallic glasses (BMGs) was systematically investigated by thermal analysis, transmission electron microscopy (TEM), the compression test, the pin-on-disk macroscopic wear test and the microscopic nanoscratch test. TEM observation revealed the formation of a second glassy phase with a few nanometers in diameter in the Zr_63.6-xCu₁₈Ni_10.4Al₈Fe_x (x = 1, 3, 5) BMGs. The results of the mechanical tests showed that although compression strength and hardness do not change much, a remarkable enhancement in plasticity occurs in the Zr_58.6Cu₁₈Ni_10.4Al₈Fe₅ BMG, which is presumably due to the restriction of the nano-scale second phase on shear banding. Phase separation was also found to promote multiple shear bands, enhanced toughness and oxidative wear, which work synergistically during the tribological test to improve the wear resistance of Zr–Cu–Ni–Al BMGs. These findings provide some insights into the wear mechanisms of dual-phase BMGs, which may offer new strategies for design and optimization of BMGs with desired wear performance.