A Study on The Deformation Features of TC16 Alloy Treated by Cold Upset Process

Abstract:

TC16 titanium alloy samples with a cold upset treatment carried on a fast upsetting testing machine were prepared. The properties and deformation structure of samples were analyzed by micro-hardness tester, TEM and XRD. The results demonstrated that the deformation was mainly because of the dislocation sliding, and the structure and properties of the deformation samples presented a certain extent of inhomogeneity. When the forging ratio was 1/6, the hardness was 300 HV which was stabilized. The hardness had increased 20% compared to the original sample. The original equiaxed crystals in the central part of the shearing band were stretched gradually with the increase of the deformation. Grain crack and refinement occurred when the grain width was less than 100 nm, which was the main reason of the stable hardness. Cracks were not observed in the central part of the sample under a larger deformation, due to the good plasticity of TC16 alloy. However, XRD showed that the martensite phase transformation had taken place during the process of the deformation.

Key words:TC16; cold upset; shear band; strengthening mechanism