Tensile and creep properties under different temperature conditions of titanium matrix composites reinforced by TiB and TiC

Abstract

In this paper, the microstructure characterization, tensile properties and creep behaviors under different temperature conditions of titanium matrix composites reinforced with 2 vol% and 4 vol% (TiB + TiC) were systematically studied. The results showed that two composites possessed the basket-weave structure with some equaixed-like α phases. The increased reinforcements reduced the length of the α lamellae and promoted the formation of TiB/TiC interfaces. The inergrowth TiB/TiC structures were stable in the tensile and creep process. Accompanied by the synergistic effect between TiB and TiC in TiB/TiC structure, the composite with higher reinforcement content possessed better tensile and creep properties under the given experimental conditions. In the creep process, α/β interfaces, reinforcements and silicides restricted the dislocation movement, promoting the dislocation rearrangement and the formation of sub-grains. The dislocation structure at 650 °C was mainly flat edge dislocations. Combined with the stress exponent, the dislocation climbing can be determined as the creep control mechanism. With the creep temperature increasing to 700 °C, the sub-grain size increased, and a large number of screw dislocations characterized by short jogs along the screw segments were observed.