Effect of β heat treatment temperature on microstructure and mechanical properties of in situ titanium matrix composites

TiB and La2O3 reinforced titanium matrix composites were in situ prepared by casting and hot working. An effort was made to investigate relationship between β heat treatment temperature, microstructure and mechanical properties. Tensile tests were performed at room temperature, 600, 650 and 700 °C, respectively. Results indicated that composites treated at 10 °C above β transus points obtained fine grain microstructures and superior mechanical properties. When composites were treated at 20 °C above β transus points, the larger α colonies sizes led extremely decreased strength and the effect of reinforcements' volume fraction on matrix of composites was reduced; dominant failure modes at high temperatures also differed from the fine microstructure.