Comparative study on bonding characteristics and bonding strengths of Si/SiC and Al/SiC interfaces based on first principles
AlSi7-SiC composite was prepared by semi-solid stirring casting,and its near-net shape forming was achieved by vacuum die casting.The influence of eutectic Si segregation on the interface strength of SiC-Al composite was studied by the first principles calculation method.The results shown that a mass of eutectic Si seg-regation was found in the matrix of the prepared AlSi7-SiC composites and three typical interfaces were formed:mixed up with a few eutectic Si,a half trapped in eutectic Si and completely trapped in eutectic Si.The calcula-tion results shown that the Si/SiC interface with C-terminated and Si-terminated,the topSi1 coordination mode has the largest adhesion work after relaxation.The interface bonding strength of the Si/SiC interface is greater than that of the Al/SiC interface.Compared with the Al/SiC interface,the Si/SiC interface had a better stability of interface structure attributed to the strong covalent bond formed at the Si/SiC interface and the segregated Si phase improved the interfacial charge density.
SiC Al matrix compositesElement segregationFirst principlesInterfacial performance
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