Improvement of mechanical properties and investigation of strengthening mechanisms on the Ti 3 AlC 2 ceramic with nanosized WC addition

作者：Yijun Zhong, Ying Liu, Qinkai Jiang, Na Jin, Zifeng Lin, Jinwen Ye · 发表于：Journal of Advanced Ceramics · 年份：2024 · DOI：10.26599/jac.2024.9220905 · 被引用次数：16 · 研究领域：MXene and MAX Phase Materials、Advanced materials and composites、Advanced ceramic materials synthesis

Ti 3 AlC 2 (TAC) has great potential for use as an ablation material in aerospace applications due to its great oxidation/ablation resistance, but its high-temperature strength and thermal shock resistance still have much room for simultaneous improvement under fast temperature variation conditions. Herein, we used Ti 3 AlC 2 and WC powders as raw materials and successfully fabricated textured (Ti,W) 3 AlC 2 ceramic with small amounts of TiC and Al 2 O 3 , and room temperature mechanical properties such as flexural strength (1146±46.9 MPa), fracture toughness (11.78±0.44 MPa·m 1/2 ), and hardness (5.81±0.11 GPa) at 5 wt% WC addition were achieved. The high-temperature strength of the ceramic was significantly improved, and better thermal shock resistance from 298 to 1173 K was simultaneously acquired together with the regulation of the elastic modulus, thermal conductivity, and thermal expansion coefficient, providing (Ti,W) 3 AlC 2 with more possibilities for fast-temperature variation applications. Strengthening and toughening mechanisms were proposed. Scanning transmission electron microscopy high-angle annular dark-field imaging (STEM-HADDF) showed that W randomly replaced the Ti 1 and Ti 2 sites of Ti 3 AlC 2 , providing a good reference for establishing crystal models, and further density functional theory (DFT) calculations based on these models indicated a higher fracture energy of (Ti,W) 3 AlC 2 along different crystal planes, providing superior resistance to ...