Abstract
Amorphous Ti-based alloys show good mechanical properties and have been investigated for a long time. However, the glass forming ability (GFA) of titanium alloys is not promising so that the development of Ti-based BMGs has been limited. The purpose of this study is to develop the new composition of Ti-based BMGs which have good GFA. The study focused on binary Ti-Co and ternary Ti-Co-M systems. The best composition we evaluated is Ti60Co40 that is far from the eutectic point in Ti-Co binary system. This is the best glass former though it consists of mixed crystalline and amorphous phases. The glass transition temperature of Ti60Co40 is 925 K and the crystalline temperature is 980 K. The nickel, tin, yttrium and zirconium were subsequently added into the binary system individually to cast cylinder with 1 mm in diameter. It shows better GFA with the addition of nickel or zirconium. The best composition of Ti-Co-Ni is Ti60Co20Ni20. The crystalline temperature of Ti60Co20Ni20 is 986 K While the best result of Ti-Co-Zr is Ti60Co36Zr4. Both systems consist of amorphous and crystalline and the size of the crystalline is about 10 nm. The glass transition temperature of Ti60Co36Zr4 is 989 K and the crystalline temperature is 1052 K.