Phase evolution in Cu54Ni6Zr22Ti18 bulk metallic glass Nd:YAG laser weld

A Nd:YAG pulse laser was chosen as the heat source to make a Cu54Ni6Zr22Ti18 bulk metallic glass (BMG) weld with a critical thickness of 6 mm. To make a crystallization-free BMG weld, both empirical and numerical approaches were conducted. For the empirical approach, the pulse shape including peak pulse power and pulse duration was pre-selected and the phase evolution in the BMG bead-on-plate was then investigated according to the pulse frequency and travel speed. Thermal cycles of heating and cooling were estimated by a numerical method. Through the results, crystallizations at each weld metal and heat-affected zone in the BMG bead on plate (BOP) weld were considered.