FE Simulation And Experimental Investigation Of The Equal Channel Angular Pressing Of Ti-6Al-4V Titanium Alloy

The material with ultra-fined grains not only has an excellent ductility, fatigue strength and thermostability, but also exhibits the good workability. The ECAP (Equal Channel Angular Pressing) is an effective way to obtain the bulk material with homogeneous ultra-fined grains by severe plastic deformation without alteration on dimensions of the sample. In this paper, FE simulation was applied to optimize the process parameters so as to obtain the better ultra-fined grains.In this paper, based on the high temperature deformation behavior, the optimal process parameters of the Ti-6A1-4V titanium alloy in high temperature deformation were obtained by the processing maps. In addition, the flow stress model was obtained, which well represented the relationship between the flow stress and the deformation temperature, strain rate and strain. The mean difference between the calculated and the experimental flow stress was 8.84%, and the maximum difference was 13.9%.Integrating the flow stress model into the FE code, FE simulation coupled deformation with heat transfer has been constructed for the ECAP deformation process of Ti-6A1-4V titanium alloy. Effect of the deformation temperature, ram velocity, shear factor of friction, and angular on the equivalent stress field, equivalent strain field, temperature field and load in the ECAP deformation process has been studied, which was based on selecting the optimal process parameters of the Ti-6A1-4V titanium alloy.Based on the optimal process parameters, the ECAP processing of the Ti-6A1-4V titanium alloy has been carried out. The microstructure and mechanical properties of the Ti-6A1-4V titanium alloys after ECAP processing at different deformation temperature, ram velocity and pressing passes were studied. To decrease the deformation temperature and increase ram velocity and pressing passes were beneficial for refining grains.