Optimization of Forging Processing Parameters in β Phase Field of Coarse Lamellar TA15 Titanium Alloy Based on Murty Criterion

Hot compression tests of TA15 titanium alloy with coarse lamellar microstructure were conducted using Thermecmastor-Z hot working simulator.Microstructural deformation mechanisms were investigated by means of processing map technology based on Murty criterion in the temperature range of 1 000-1 100℃ and strain rate range of 0.001-10 s-1,and the forging thermal parameters were optimized.The results show that in β phase field the desired deformation regions were in the range of 1 030-1 075℃ and 0.001-0.03 s-1 with the deformation mechanism of full and uniform dynamic recrystallization,and the optimum deformation parameters were at 1 050℃ and 0.001 s-1.The regions of flow instability occurred in the temperature range of 1 000-1 100℃ and strain rate range of 1.78-10 s-1,and non-uniform deformation of β grains appeared in this range.