In-situ TiC/Ti composites based on Ti2AlC–Ti system: Reaction process, microstructure, and mechanical properties

Abstract

Based on the improvement of the phase transition temperature of Ti by Al element and the excellent strengthening effect of TiC particles, this paper selects Ti2AlC as the precursor, striving to improve the high-temperature performance of the Ti matrix. The composites with 1–10 vol% Ti2AlC addition were fabricated by hot-pressing sintering. And a detailed study was conducted on the reaction process, microstructure, room and high temperature compression properties of the composites. The experimental results show that the separation of Al elements at the A-position occurs at around 700 °C in Ti2AlC, and the Al element is homogenized in the matrix during the subsequent sintering process. Micron sized TiC particles are mainly distributed at the Ti grain boundaries, while the content of sub-micron sized TiC particles entering the crystal increases with the increasing Ti2AlC addition. The interface mismatch between TiC and Ti is small, and the bonding is well. These microstructures enable composite materials to exhibit excellent mechanical properties, with 10 vol% Ti2AlC/Ti composite having a yield strength of 1858 MPa and an ultimate strength of 2200 MPa at room temperature, and maintaining a yield strength of 602 MPa and an ultimate strength of 1264 MPa at 500 °C.