Finite element simulation and experimental study of single-laser track in laser polishing of Ti6Al4V

Laser polishing is a promising surface finishing technique aimed at improving surface quality. Single-line scanning is the premise of the entire surface polishing. This paper developed a three-dimensional transient finite element model which described the distribution of temperature and stress field in the single-laser scanning. Meanwhile, the molten pool width was predicted by the model, and then verified by experiments. The results illustrated that high temperature and significant thermal gradient would occur near the heat source, which easily led to residual stress. The stress components were different, forming anisotropic stress distribution in the part, and the maximum stress component (σx) was along the scanning vector direction. The errors between the predicted values and the experimental values of the molten pool width were mostly less than 10%. The cross-sectional metallographic diagram showed that the typical micro-structure of SLM Ti6Al4V alloy was columnar β crystal and acicular α′ martensite. This provides a basis for optimizing and improving surface laser polishing technology.