Quaternary Ti–Zr–Be–Ni bulk metallic glasses with large glass-forming ability

The glass-forming ability (GFA) of Ti–Zr–Be ternary alloys is dramatically improved by partially replacing Be with Ni. Centimeter-scale fully amorphous samples can be obtained in a wide Ni content range of 4at.%–12at.%. In particular, some of the developed Ti–Zr–Be–Ni alloys exhibit a critical diameter up to 20mm, which is larger than that of other quaternary Ti-based bulk metallic glasses (BMGs). Moreover, Ni addition also enhances the yield strength and compressive plastic strain of Ti–Zr–Be alloys obviously. Based on the experimental results, the effect of substituting elements addition on the glass-forming ability of Ti–Zr–Be alloys has been systematically investigated and an empirical composition design method for the development of novel Ti-based BMGs with large GFA has been proposed. [Display omitted] •The newly developed Ti–Zr–Be–Ni alloys exhibit superior glass-forming ability (GFA).•The Ti–Zr–Be–Ni bulk metallic glasses (BMGs) have a critical diameter up to 20mm.•This is the largest size in the quaternary Ti-based BMGs reported so far.•Empirical rules are proposed for developing novel Ti-based BMGs with large GFA.