Improvement of mechanical properties and investigation of strengthening mechanisms on the Ti_(3)AlC_(2) ceramic with nanosized WC addition  

作　　者：Yi Zhong Ying Liu Qinkai Jiang Na Jin Zifeng Lin Jinwen Ye 

机构地区：[1]School of Materials Science&Engineering,Sichuan University,Chengdu 610065,China [2]Yibin R&D Park,Yibin Industrial Technology Research Institute,Sichuan University,Yibin 644005,China

出　　处：《Journal of Advanced Ceramics》2024年第6期861-876,共16页先进陶瓷（英文）

基　　金：financially supported by The 2021 Strategic Cooperation Project between Sichuan University and the People’s Government of Luzhou(2021CDLZ-1);Demonstration of industrialization and Application of TiCN based Ceramic Materials(2023ZHJY0016);Development of High Performance Nitrogen-Containing Carbide Materials and Key Technologies of CNC Tools based on Vanadium Titanium Rare Earth Carbonitride Solid Solution Powder.

摘　　要：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 Ti1 and Ti2 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 transgranular fracture;a lower mismatch degree of (Ti,W)_(3)AlC_(2)/Al_(2)O_(3) resulted in stronger interface bonding, resulting in greater resistance to intergranular fracture as well as more balanced stress distributions at different interfaces.

关 键 词：mechanical properties solid solution MAX phase transmission electron microscopy(TEM) CERAMIC atomic structure 

分 类 号：TQ174.1[化学工程—陶瓷工业]