A novel superhard phase of TiB3 predicted by first-principles calculation

• Published in: Results in physics 2024-06, Vol.61, p.107779, Article 107779
• Main Authors: Chen, Meng-Ru, Dou, Xi-Long, Song, Ting, Yan, Zhi-Peng, Sun, Xiao-Wei
• Format: Article
• Language: English
• Subjects: High pressure; Mechanical properties; Phase transition; Structure prediction; TiB3
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2024.107779

•A novel superhard structure of TiB3 with the space group Amm2 is predicted.•It exhibits a hardness of up to 51.6 GPa, 3.2 GPa higher than the C2/m structure.•The newly proposed structure emerges as the toughest Ti-B compound identified to date. A novel superhard structure of TiB3 is predicted and its phase transitions, mechanical properties and electronic structure up to 200 GPa are studied employing first-principles calculation. We propose a new structure by substituting the highly stable Amm2 structure with excellent mechanical properties in VB3. Enthalpy calculations demonstrate its superior energetic stability compared to the previously predicted C2/m structure via particle swarm optimization. Furthermore, it maintains stability up to 93.8 GPa and transforms into a P2/m structure under further compression. The Amm2 structure stands as a novel superhard phase with a hardness of 51.6 GPa by Chen’s model, surpassing the C2/m structure by 3.2 GPa. This disparity arises from structural distinctions, with the Amm2 structure featuring boron plates consisting of more layers, resulting in stronger B-B interactions. This novel superhard structure stands as the hardest reported Ti-B compound to date, poised to replace conventional superhard material c-BN in cutting tools and wear-resistant coatings.