Research on surface residual stresses generated by milling Ti6Al4V alloy under different pre-stresses

Abstract

Machining-induced residual stress plays a significant role in the corrosion resistance and fatigue life of the manufacturing end product. In the current study, milling experiments were performed to investigate the influence of pre-stress on the surface residual stresses. For this purpose, finite element (FE) simulations of the orthogonal cutting based on arbitrary Lagrangian-Eulerian approach were performed. To validate the simulation results, a device was designed to stretch the workpiece with pre-stresses before the machining process. The residual stresses obtained under different pre-stresses were measured based on the varied bending deflection of the workpiece after each material layer removal. As a result, the general variation trend of residual stress profiles that obtained under different pre-stresses was found well consistent with the finite element simulation results, indicating that the proposed residual stress measuring principle is reliable. Furthermore, the pre-stress loaded on the Ti6Al4V part can significantly affect the distribution of machining-induced residual stresses, implying that surface residual stresses can be adjusted by employing appropriate values of pre-stresses during the machining process.