Ti3AlC2−yNy carbonitride MAX phase solid solutions with tunable mechanical, thermal, and electrical properties

• Published in: Journal of advanced ceramics 2024-09, Vol.13 (9), p.1473-1481
• Main Authors: Weiwei Zhang, Shibo Li, Shukai Fan, Xuejin Zhang, Xiachen Fan, Guoping Bei
• Format: Article
• Language: English
• Subjects: electrical conductivity; max solid solutions; mechanical properties; microstructure; thermal expansion; ti3alc2−yny
• ISSN: 2226-4108; 2227-8508
• DOI: 10.26599/JAC.2024.9220951

Changing the N content in the Ti3AlC2−yNy MAX phase solid solutions allows for the fine-tuning of their properties. However, systematic studies on the synthesis and properties of Ti3AlC2−yNy solid solution bulks have not been reported thus far. Here, previously reported Ti3AlC2−yNy solid solution bulks (y = 0.3, 0.5, 0.8, and 1.0) were synthesized via hot pressing of their powder counterparts under optimized conditions. The prepared Ti3AlC2−yNy bulks are dense and have a fine microstructure with grain sizes of 6–8 μm. The influence of the N content on the mechanical properties, electrical conductivities, and coefficients of thermal expansion (CTEs) of the prepared Ti3AlC2−yNy bulk materials was clarified. The flexural strength and Vickers hardness values increased with increasing N content, suggesting that solid solution strengthening effectively improved the mechanical properties of Ti3AlC2−yNy. Ti3AlCN (y = 1) had the highest Vickers hardness and flexural strength among the studied samples, reaching 5.54 GPa and 550 MPa, respectively. However, the electrical conductivity and CTEs of the Ti3AlC2−yNy solid solutions decreased with increasing N content, from 8.93×10−6 to 7.69×10−6 K−1 and from 1.33×106 to 0.95×106 S/m, respectively. This work demonstrated the tunable properties of Ti3AlC2−yNy solid solutions with varying N contents and widened the MAX phase family for fundamental studies and applications.