Stability, mechanical and electronic properties of ceramic interphases in biomedical composites via first-principles calculations

Abstract

To study the effects of ceramic interphases (such as CaO, Ti2O, Ti5P3, CaZrO3, CaTiO3, etc.) on the properties of Ti-based composites which are of great interest in the biomedical industry with the potential to replace Ti alloy implants, the thermodynamic stability, mechanical and electronic properties, and Debye temperature of ceramic interphases were investigated by means of first-principles calculations. The results show that ceramic interphases exhibit different stability (CaZrO3 > CaTiO3 > CaO > Ti2O > Ti5P3). The mechanical properties of ceramic interphases have strong anisotropy because of the large calculated anisotropic index and obvious different shape of surface contour for Young's modulus. The ceramic interphases are almost brittle, and have larger hardness, Young's modulus and shear modulus than that of α-Ti and β-Ti. However, Ti5P3 appears relatively good toughness compared to other ceramic interphases due to the largest B/G value of 1.85. It is worth noting that Ti2O has the largest Young's modulus of 293.7 GPa and highest hardness of 18.6 GPa. The Debye temperature (ΘD) results indicate that CaTiO3 has the largest ΘD value among these ceramic interphases, which indicates that the chemical bonds in it are stronger than other ceramic interphases. Moreover, Ti5P3 has the lowest Debye temperature.