Crack Propagation Behavior of TiB+TiC+La₂O₃ Ternary Particulate Reinforced IMI834 Titanium Matrix Composite

TiB+TiC+La₂O₃ ternary particulate reinforced IMI834 titanium matrix composite was in-situ synthesized, and then forged and treated by stress relief annealing. The microstructure, tensile properties and the crack propagation behavior of the composite were investigated. The results show that the in-situ synthesized TiB, TiC and La₂O₃ reinforcements dispersed homogenously in the titanium alloy matrix, forming a clean interface, and some TiB reinforcements were broken. The yield and tensile strength of the composite were 1 010 MPa and 1 150 MPa, respectively, improved by 9% and 8% compared with those of IMI834 titaniuim alloy. Intergranular crack propagation mainly occurred in the region containing fewer defects of the composite, and the crack propagation path was tortuous. In the region containing more defects, defects caused by broken reinforcements changed the crack propagation direction.