The effect of heat treatment on mechanical properties of in situ synthesized 7715D titanium matrix composites

7715D titanium matrix composites (TMCs) reinforced with TiB, TiC and La2O3 were in situ synthesized by common casting and hot-forging technology. Two kinds of heat treatments were adopted. Fully lamellar microstructures and equiaxed microstructures were obtained by annealing in β and α + β phases, respectively. The tensile properties of the composites at both ambient and elevated temperatures and also the creep rupture properties were tested. The TMCs with fully lamellar microstructures show superior comprehensive properties in comparison with those with equiaxed microstructures. Lamellar microstructure retarded the crack propagation which originated from cracked whisker more effectively. The strengthening effect of reinforcements can be given full play for the composites with lamellar microstructures.