Mechanical behavior of bilayer Ti6Al4V composite under quasi-static and dynamic compression

Bilayer structure and homogeneous structure of Ti6Al4V (TC4) alloy were fabricated by High energy ball milling (HEBM) and Fast Hot-Press Sintering (FHPS). The flake TC4 (F-TC4) powders were obtained from spherical TC4 (S-TC4) powders by HEBM, and the bilayer F/S-TC4 composite was prepared from F-TC4 and S-TC4 powders. The microstructure and micro-hardness evolution along the interface of the bilayer composite were investigated. It was found that the hardness decreased gradually from the F-TC4 side to the S-TC4 side. Moreover, an obvious morphology difference in the interface was observed, typical Widmanstatten structure on the S-TC4 side while an equiaxed structure on the F-TC4 side. In addition, the mechanical properties of the alloy and composite with different structures were studied under quasi-static and dynamic compression. The results revealed that the bilayer F/S-TC4 composite showed great strength improvement with little plasticity sacrifice as compared to traditional S-TC4 alloy.