Numerical simulation study of ultraviolet nanosecond laser ablation of Cu-Al2O3 dispersion strengthened alloys

Abstract

A finite element model of nanosecond laser interaction with the Cu-Al2O3 dispersion strengthened alloys has been established according to the underlying mechanism of melting flow, phase transition and evaporation removal of material. Attempting to replicate the multi-field coupling effects in laser ablation process, this model takes both the thermophysical properties of materials varied with the temperature, and the evolution of erosion morphology under the instantaneous high-temperature action of pulsed laser into consideration. Moreover, the influence of coaction of diverse forces (including recoil pressure, surface tension, Marangoni force), the phase transformation and melting flow of material on the laser processing were also integrated into the model. On the basis of the proposed model, a FEM simulation study on the distribution of temperature field, formation process of erosion morphology, and numerical prediction of ablation depth in laser processing was performed. The deviation of the predicted values of ablation depth from the experimental results under the same power condition as the simulations can be controlled within 13%, indicating that the proposed simulation model can be adopted to effectively predict the width of heat affected zone and the width of recast layer under specific processing parameters.