Effect of Heat Treatment on Microstructure and Properties of Laser DepositionTC4 / TC11

Abstract:

By comparing the microstructure, static mechanical properties, tensile fracture and microhardness of laser deposited TC4 / TC11 titanium alloy direct transitional parts in the as-deposited and heat-treated states, the approaches to perfect the microstructure of laser deposition TC4/TC11 alloy so as to improve its integrated mechanical properties were explored,. Results show that after the as-deposited sample undergoes 970℃ heat treatment, its length-width ratio of α laths is less than that of as-deposited and annealed samples. The microstructure on the two sides is featured by basket-weave structure and more even. In addition, the grain boundary α disappears entirely. There is almost no existence of transitive interface, which optimizes the textural parameters of TC4/TC11 titanium alloy. For all the as-deposited, relieved-stress and solution aging samples (optimal heat treatment parameters), their tensile fractures are tough fracture and their fracture sections are all on the side of TC4 titanium alloys. Among them, the strength of solution aging sample is not reduced greatly. Moreover, its plasticity is remarkably enhanced. So it has excellent integrated mechanical properties. When the temperature of the heat treatment raises to 970℃ (optimal heat treatment parameters) microhardness of TC4/TC11 titanium alloys is uniform along the whole transitive interface with minimum differences. At the same time, microhardness changes the most slightly on the matrix and transitive interface.