Investigation on abrasive wear mechanism of single diamond grain in flexible scribing titanium alloy

Abstract

Abrasive belt grinding technique has been gradually used in precision machining those attractive materials of aerospace field. The excellent performance of rigid-flexible composited diamond belt shows great application prospect while its abrasive wear mechanism is deeply revealed. Therefore, a series of theoretical and experimental studies are performed to explore the wear mechanism of single diamond grain in flexible scribing titanium alloy in this work. Three-dimensional finite element simulation model was built to investigate the elastic frictional wear process between a diamond grain and the titanium alloy sample under different combinations of processing parameters. The simulation results showed that the normal force and grain size contributed much to frictional stress and the friction speed had the greatest effect on the frictional temperature. On this basis, the flexible scribing experiments of titanium alloy sample by using single diamond grain were conducted to verify the effect of scribing parameters on diamond grain wear. Raman scattering analysis, chemical thermodynamic calculation and X-ray photoelectron spectroscopy analysis methods were proposed to further research the essential wear of diamond grain at elevated temperature. The results indicated that the physical wear caused by higher scribing force was the main pattern at lower temperature. When the temperature reached up to 1100 K, Raman shifts peak of graphite corresponding to 1544 cm−1 was detected to illustrate the graphite transformation of diamond crystal structure, and the existence of TiO2 and CO bond were confirmed to explain the oxidation wear of diamond grain at the atmosphere of air medium. This research work provides an important theoretical basis for restraining the diamond belt wear in precision grinding operation of titanium alloys.