Influence of matrix characteristics on tensile properties of in situ synthesized TiC/TA15 composite

In the present paper, in situ synthesized 10 vol.% TiC/TA15 composite has been fabricated by induction melting and common casting utilizing the reaction between titanium and C powder. Three types of heat treatment processes were performed on the as-cast composite and, accordingly, fine fully lamellar, bimodal and near-equiaxed microstructures were obtained. The tensile properties were tested at room temperature, 600 degrees C and 650 degrees C. The results show that heat treatment can evidently enhance UTS below 600 degrees C. The increased UTS is accompanied by the rapid decrease in tensile elongation at room temperature. As tensile temperature increases to 650 degrees C, the discrepancy in UTSs of the composite with different matrix microstructures becomes small. The composite with fine fully lamellar microstructure exhibits a good combination of relatively high UTS and high tensile elongation in comparison with that with bi-modal and near-equiaxed microstructures. Below 650 degrees C, the damage of the composite before and after heat treatment is mainly initiated by the fracture of TiC particles followed by the ductile failure of the matrix. (C) 2012 Elsevier B.V. All rights reserved.