Hardness in rare earth diboride systems: Ab initio full-potential study. (January 2017)

• Record Type: Journal Article
• Authors: Zaoui, A.; Abderrahmane, S. Ait; Djermouni, M.; Kacimi, S.; Zazoua, F.; Boukortt, A.; Bejar, M.; Dhahri, E.
• Is Part Of: Superlattices and microstructures. Volume 101(2017)
• Page Start: 575
• Page End: 583
• Publication Date: 2017-01
• Subjects: DFT -- Elastic constants -- Hardness -- Diborides -- Rare earth elements; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2016.10.020
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: We study in this paper the macroscopic hardness of TiB2 and TmB2 compounds and their corresponding ternary alloys Tm1−x Tix B2 by calculating the mechanical properties and electronic structure of these systems. The mechanical results show that TiB2 compound is found ultra-hard compared with TmB2 and the covalent BB bonds have an enormous impact on the macroscopic hardness of these systems. These results are in excellent agreement with experiment. In addition, a large charge density was observed in the TiB2 compound comparing to that of TmB2 and of the considered alloys. For short interatomic distances BB, the hardness in Tm1−x Tix B2 alloys is important. Highlights: LSDA + U calculations were performed on Tm1−x Tix B2 alloys. The mechanical properties and electronic structure has been studied and discussed. BB bonds play a more important role than the Ti (Tm)B interaction in these systems. The covalent bond BB is responsible for the hardness in these systems.