Achieving ultrahigh-specific strength and enhanced GFA in Ti-based bulk metallic glasses via a two-step alloying strategy

Ti-based bulk metallic glasses (BMGs) have attracted increasing attention due to their high specific strength. However, a fundamental conflict exists between the specific strength and glass-forming ability (GFA) of Ti-based BMGs, restricting their commercial applications significantly. In this study, this challenge was addressed by introducing a two-step alloying strategy to mitigate the remarkable density increment effect associated with heavy alloying elements required for enhancing the GFA. Consequently, through two-step alloying with Al and Fe in sequence, simultaneous enhancements in specific strength and GFA were achieved based on a Ti–Zr–Be ternary metallic glass, resulting in the development of a series of centimeter-sized metallic glasses exhibiting ultrahigh-specific strength. Notably, the newly developed (Ti₄₅Zr₂₀Be₃₁Al₄)₉₄Fe₆ alloy established a new record for the specific strength of Ti-based BMGs. Along with a critical diameter (D_c) of 10 mm, it offers the optimal scheme for balancing the specific strength and GFA of Ti-based BMGs. The present results further brighten the application prospects of Ti-based BMGs as lightweight materials.