The interface bonding properties of Mg/SiC composite doped with Zr, Al, and Zn elements: A first-principles study

In order to improve the mechanical properties of silicon carbide composite materials based on magnesium, Zr, Al, and Zn are frequently utilized as alloying elements. The mechanical properties of the composite material are closely related to the interface bonding strength. Theoretical calculations on the impact of adding components on the strength of the interface bonding are currently not thorough enough. In this work, the first-principles calculations are performed to investigate the impact of doping Zr, Al, and Zn elements in the Mg matrix on the interface bonding of 6 H-SiC/Mg and the effect of alloy elements on the interface stability and electronic structure in composite interfaces. The results showed that Al and Zn elements may segregate from the interface in the form of a second phase, whereas Zr elements are difficult to segregate from the Mg/SiC composite interface. Zr tends to increase the stability of the Mg/SiC composite interface over the full range of triangle mu(Si), whereas Al and Zn tend to weaken it. In addition, the stability order of the doped interface is Zr>Al>Zn. The electronic structure of the doping interface shows that the bonding at the interface is both ionic and covalent. The segregation behavior of doped elements at the interface and the variation in covalent bonding strengths between interfaces are the primary variables impacting interface bonding. The internal cleavage layer of the composite material's adhesion work can be examined to reveal that the composite interface is not the material's probable fracture failure point.