Elastic properties, hardness, and anisotropy in baddeleyite IVTMO2 (M=Ti, Zr, Hf)

• DOI: 10.1007/s40843-015-0098-2
• Publication Date: 2015-12-01T14:46:08Z
• Authors: Zhi-Qian Chen; Feng Li; Meng Hu; Chun-Mei Li
• Keywords: Baddeleyite

In this article, we used plane-wave density functional theory to investigate the elasticity, anisotropy, and minimum thermal conductivities of baddeleyite type the IVTMO2 (m-TiO2, m-ZrO2, and m-HfO2). The elastic constants and modulus, Poisson’s ratio, hardness, sound speed, Debye temperature, and minimum thermal conductivities at high temperature were calculated. These calculations show that m-MO2 is not superhard, with a hardness range of about 8–13 GPa. Among these materials, m-TiO2 is the hardest, while m-HfO2 is the least hard. Their elastic and plastic anisotropy are given in detail. Moreover, the m-HfO2 thin film is the most likely to develop microcracks during preparation because it has the highest elastic anisotropy. Among the three dioxides, m-HfO2 is the best thermal barrier because it has the lowest thermal conductivity.