Effect of reinforcements on high temperature mechanical properties of in situ synthesized titanium matrix composites

摘要

Four types of high temperature titanium matrix composite reinforced with multi-dimensional reinforcements are synthesized by common casting and hot-forging technology utilizing the reaction between Ti and LaB_6, B_4C. The microstructure and tensile properties at elevated temperature of the composites are characterized and tested. The strengthening mechanism of composites can be summarized as two main reasons: the load bearing effect of TiB short fibers and dispersion strengthening effect of TiC/La_2O_3 particles. The effect of TiB short fibers on high temperature strength is quite different from room temperature. The composite with the lowest volume fraction of reinforcements shows the best high temperature mechanical properties due to the efficient strengthening of TiB whiskers in the whole high temperature range.