Microstructure and properties of direct transition interface of TC4/TC11 fabricated by laser deposition

Abstract:

TC4/TC11 direct-transition alloy samples were prepared by laser deposition technique, and the stress relief and solution aging heat treatments were carried out. The microstructure, tensile fracture were observed using optical microscope (OM), scanning electron microscopy (SEM) and universal testing machine, then the tensile properties and hardness were tested and analyzed. The results show that the basket-weave microstructures of two sides of the deposited TC4/TC11 differ greatly, the microstructure is much more uniform after stress relieving and the microstructure is coarser after solution-aging. After the tensile tests under ambient temperature on the stress-relieved samples, the minimum tensile strength of TC4/TC11 is located at the direct transition zone, which is close to that of TC4. TC4/TC11 has a low plasticity at the direct transition zone. The fracture sections at room temperature are all on the side of TC4 titanium alloy, which proves that the direct transition interface of TC4/TC11 has good properties. The microstructure analysis of the direct transition zone explains its micro-hardness variation.