Papers by Keyword: Titanium Alloy TC11

Abstract: During the metal hot working process, the dislocation density will vary with strain and strain rate, and the variation of the dislocation density will affect the grain evolution subsequently. The cellular automaton (CA) method is an effective technique used to simulate the grain evolution of materials. In this work, a dynamic recrystallization (DRX) model of titanium alloy TC11 under varied strain rates was established by the use of cellular automaton method and verified by experimental observation. Two types of loading processes called “begin fast and then slowly” and “begin slowly and then fast” were simulated to investigate the titanium alloy TC11 grain evolution processes during hot working. The simulation results are in good coincidence with experimental data. Both cellular automaton simulation and experimental results show that the flow stresses and DRX transformation percentage during hot working process of the TC11 alloy are closely related not only to the strain rate but also to the loading sequence. Compared to the “begin slowly and then fast” loading sequence, the flow stress with the “begin fast and then slowly” loading sequence is relatively smaller under the same strain rates, and the DRX transformation percentage is relatively larger.

Abstract: In order to provide experimental evidence for optimizing high-speed milling parameters and controlling surface integrity, the effects of cooling conditions, tool rake angle and milling parameters on machined surface residual stresses were investigated in high-speed milling titanium alloy TC11. The residual stresses were measured by XStress3000 X-ray stress analyzer, and three points were tested on each workpiece surface, then take average. The milling parameters were optimized based on fatigue performance. The results show that the emulsion cooling get the highest surface residual compressive stress and the dry cutting get the lowest residual compressive stress. With the increasing of cutting tool rake angle, surface residual compressive stresses increase. The most effect on the residual stresses of surface is milling width, next are feed per tooth and milling depth, and the last is milling speed. In the experimental range, the optimized high-speed milling parameters are: vc=377m/min, fz=0.03mm/z, ap=0.2mm, ae=7.5mm.