Improved mechanical properties and pitting corrosion resistance of Zr₆₅Cu_17.5Fe₁₀Al_7.5 bulk metallic glass by isothermal annealing

Isothermal annealing has been used to improve the mechanical properties and the pitting corrosion resistance of a new bulk metallic glass (BMG) alloy, Zr₆₅Cu_17.5Fe₁₀Al_7.5. The as-cast alloy was annealed at the temperature below the glass transition temperature (T_g) for 0.5, 1.0, 2.0, and 4.0 h. A considerable large plasticity of 7.1% is achieved in the alloy annealed for 1.0 h without loosing its strength, which can be attributed to the formation of nanocrystallites with diameter 5–12 nm in the glassy matrix. In addition, presumably due to the decrease in the free volume, appropriate annealing (t = 0.5 and 1.0 h) can increase the pitting corrosion resistance significantly of the as-cast alloy. Thus, Zr-based metallic glass matrix composite has a promising potential for engineering and biomedical applications.