Microstructure and crystallization mechanism of Ti-based bulk metallic glass by electron beam welding

In this work, we report on the successful welding of the Ti-based bulk metallic glass (BMG) plates via electron beam welding route. Microstructure determination shows that crystalline phases exist both in weld zone (WZ) and heat affected zone (HAZ). The critical cooling rate for glass formation in WZ is depended on the solidification condition. The continuous heating transformation curve (CHT) of glass transition temperature (T_g) and crystallization temperature (T_x) during heating process, time-temperature-transformation diagram (C-curve) during cooling process, and the thermal cycle curves are obtained by Kissinger equation, nucleation theory, and temperature field simulation, respectively. The crystallization mechanism in HAZ was discussed in details during the heating and cooling processes. The intersection between cooling curve and C-curve denotes the crystallization of HAZ during the cooling process.