Promoting wetting of Mg on the SiC surfaces by addition of Al, Zn and Zr elements: A study via first-principle calculations

When preparing SiC/Mg composites, alloy elements play key roles in the nucleation and interfacial wetting. In this paper, effects of Al, Zn and Zr additions on the Mg/SiC interfacial bonding properties were investigated comprehensively via method of first-principle calculations. Mg(0001)/SiC(0001) interfaces with different terminations and stacking sequences were built and C II-T C II top interface has the largest work of adhesion (W-ad). Zn dopants can not improve the Wad for both C-T and Si-T interfaces. Al atom can only strengthen the C-T interface. Zr addition can greatly improve the W-ad for both C-T and Si-T interfaces. W-ad of C-T interfaces can reach up to 11.55 J/m(2) and 12.55 J/m(2) after doping 1 monolayer (ML) of Al and Zr atoms. Larger W-ad can lead to lower contact angles of Mg on SiC surfaces, which can improve wetting and nucleation in SiC/Mg composites. Analysis of electronic structure shows that Al-C and Zr-C bonds have more covalent composition than the Mg-C bond, which is responsible for the improvement of interfacial bonding strength. Experimental results in references were also analyzed, which are in well agreement with our calculation results. (C) 2019 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.