Micro-stiffener surface characteristics with belt polishing processing for titanium alloys

Abstract

Titanium alloys with effective material characteristics are widely applied to the design of significant components of aero-engines, such as the blisk, blade, and commutator, and it is very important to create under requirement surface integrity to improve fatigue life by using advanced manufacturing technology, under the requirements of surface integrity for titanium alloy parts. In this paper, the method of micro-stiffener belt polishing (MSBP) is presented to realize anti-fatigue surface, which is based on the influence rule of the thin-plate stiffener on the bending life and the micro-crack principle. Thereafter, the surface characteristics and formation of titanium alloy MSBP are revealed by comparing analyses of the different polishing processes, using numerical simulation and advanced measuring. The belt polishing processes of reciprocating and high-speed rotation are used to form the micro-stiffener and smooth surface, respectively, while the different surface characteristics are obtained by adjusting the feeding speed and pressure. The formation rules of the surface characteristics are analyzed according to material removal under flexible contact conditions. The surface topography is expressed by the wavelet transform and polishing moving model, following which the surface topography is analyzed by means of comparison with the electron microscope test results. The workpiece surface residual stress is tested by an X-ray projector, and the distribution of different depth residual stresses is predicted by finite element analysis. The surface profile is obtained by a contour-graph, based on which the surface roughness distribution is obtained. The experimental results demonstrate that the surface characteristics, surface topography, surface roughness, and residual stress all meet the requirements. Furthermore, the micro-stiffener surface characteristics are superior to those of the smooth surface, particularly in terms of consistency. Therefore, the new method can be used to improve the surface integrity characteristics using the micro-stiffener for titanium alloy materials.