Centimeter-sized Ti-rich bulk metallic glasses with superior specific strength and corrosion resistance

Since increasing Ti content in Ti-based metallic glasses would benefit their specific strength, developing Ti-based bulk metallic glasses (BMGs) with high Ti content has drawn great attention of researchers. However, excessive Ti content usually deteriorates their glass forming ability (GFA), especially for Ti-based BMGs with Ti content higher than 50 at.%. Here, based on the Ti55Zr15Be20Ni10 BMG with a critical diameter of 5 mm, the (Ti55Zr15Be20Ni10)100-xFex alloys were designed and investigated. The (Ti55Zr15Be20Ni10)96Fe4 BMG exhibited a critical diameter of 10 mm, suggesting GFA of the Ti55Zr15Be20Ni10 BMG could be improved by Fe addition. In addition, their yield strength increased with Fe addition, thus the specific strength was enhanced from 3.98 × 105 N m/kg to 4.46 × 105 N m/kg, providing the most optimal scheme of specific strength and GFA among the reported Ti-based BMGs. The developed BMGs exhibited high pitting potentials in 3.5 wt.% NaCl aqueous solution, which were 1.8~2.8 times higher than that of 304 stainless steel. The present result shows that the developed Ti-based BMGs containing high Ti content, combined with high specific strength, large glass forming ability and good corrosion resistance, are promising for applications requring lightweight alloys.