Microstructure, mechanical properties and reinforcement mechanism of dual-scale TC4 titanium alloy prepared by cryomilling and plasma activated sintering

In this paper, dual-scale Ti-6Al-4V titanium alloys were prepared by cryomilling and plasma activated sintering. The microstructure and mechanical properties of the samples with different structural organizations were investigated. The relative densities were evaluated by the drainage method. The microstructure and mechanical properties were characterized by OM, SEM, XRD, EBSD, TEM, universal testing machine and Vickers hardness test methods. The results show that the dual-scale Ti-6Al-4V titanium alloy with high strength can be prepared in a relatively short time by cryomilling and plasma activated sintering. The scale structure of the alloy is controlled by a relative amount of ball-milled powders. With the ball-milled powder content increases, the fraction of the beta phase and the axial fine crystalline region is increasing. The dual-scale structure renders and the mechanical properties of the samples are more superior to the coarse crystal samples. In addition, the plastic deformation capability of the dual-scale structure is better than that of fine crystal samples. A relative density of 98.54%, the enhanced mechanical properties, including offset yield strength of 1544.19 MPa and a Vickers hardness of 427 HV were achieved, which is attributed to the different dual-scale structures.