Evolution of the supercooled liquid region and STZ in laser assisted scratching Cu50Zr50 amorphous alloy

Amorphous alloys possess increased mechanical strength. Currently, the processing and shaping of amorphous alloys employ their superplasticity in the supercooled liquid phase, which has pushed research into the evolution behavior of the supercooled liquid area during the processing of amorphous alloys. In this study, a molecular dynamics technique was applied to analyze the development rules of the supercooled liquid area and the "shear transformation zone" during laser-assisted scratching of Cu50Zr50 amorphous alloy. It was discovered through research on temperature fluctuations that laser irradiation raises the temperature of the processing region, and the formation of the supercooled liquid region moves the characteristic point of material removal to an earlier stage. As the local temperature rises, the distribution of the supercooled liquid region changes from dispersed to an angle of about 30 degrees with regard to the scratching direction, and the angle subsequently decreases. The variable laws of the "shear transformation zone" during the scratching process were explored based on the von Mises strain theory. The findings demonstrate that when laser energy rises, the Newtonian layer warms up and the "shear transformation zone" distribution angle gradually decreases. At 20 eV/ps, the angle between the "shear transformation zone" and the scratching direction achieves its smallest value of 33 degrees, resulting in the largest overlap with the supercooled liquid region and the lowest content of the "shear transformation zone". By constructing a mathematical model for material removal efficiency, it was established that energy in the range of 20 eV/ps to 30 eV/ps demonstrates higher removal efficiency and a steady processing process while reducing surface roughness by 6-7%.