Effect of cutting process adjustment on crystallographic texture of machined surface layer of titanium alloy

Integral structural parts of titanium alloy have high material removal rate, high machining difficulty and need multi-step machining to form the final geometry. The crystallographic texture of machined surface layer will affect the surface quality and the mechanical performance of machined parts from the microstructural aspect. Therefore, high requirements for finish machining surface quality and a reasonable high-quality machining surface-oriented process adjustment method need to be explored. In this paper, the surface quality controlling methods of titanium alloy machining are theoretically analyzed, two machining process adjustment methods in terms of multi-step cutting and prestressed cutting are proposed, and the finite element simulation of multi-step cutting and prestressed cutting was carried out. According to the principle of crystallographic texture and the obtained shear strain and strain rate data by finite element simulation, the crystallographic texture of surface layer materials processed by single-step cutting, single-step prestressed cutting, multi-step cutting and prestressed multi-step cutting were simulated by viscoplastic self-consistent (VPSC) texture simulation program. The influence of cutting process adjustment method on the texture polar figures (texture type and texture density) and crystallographic orientation distribution function (ODF) diagram of machined surface was analyzed. Moreover, the experimental comparisons and validations of simulated results were conducted by orthogonal cutting tests and microstructural texture measurements by using electron backscatter diffraction (EBSD) technique.

Automated summary

This paper investigates the surface quality control methods in titanium alloy machining, proposes two machining process adjustment methods, carries out finite element simulation, and validates the results through experiments.