Abstract The substitution of Si atoms in the Ti 2 AlC ceramics has been observed in the Ti 2 AlC brazing joints using AlSi eutectic filler alloy, contributing to the formation of Ti 2 (Al, Si)C solid solution in the interaction area according to the SEM analysis. Afterwards, a detailed characterization was performed using FIB/TEM technique. A remarkable decrease in the lattice constants has been observed in the modified Ti 2 AlC ceramics, and the presence of Si element in the corresponding area has been further proved by STEM. The formation and decomposition mechanisms of the Ti 2 (Al, Si)C solid solution have been studied via ab initio calculations. The results suggest that all the Ti 2 (Al 1- x , Si x )C structures with different Si contents are stable in the vibration aspect. However, due to the lower Gibbs energy of the competing phases, the structures with high Si content would decompose. Finally, the bulk Ti 2 (Al 0.9 , Si 0.1 )C has been successfully synthesized using SPS method.

中文翻译：

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Ti 2 AlC陶瓷中Si原子的取代行为

摘要 在使用 AlSi 共晶钎料的 Ti 2 AlC 钎焊接头中，观察到 Ti 2 AlC 陶瓷中的 Si 原子取代，有助于在相互作用区形成 Ti 2 (Al, Si)C 固溶体。扫描电镜分析。之后，使用 FIB/TEM 技术进行了详细的表征。在改性的 Ti 2 AlC 陶瓷中观察到晶格常数显着降低，并且 STEM 进一步证明了相应区域中存在 Si 元素。Ti 2 (Al, Si)C 固溶体的形成和分解机制已经通过从头计算进行了研究。结果表明，不同Si含量的Ti 2 (Al 1- x ，Si x )C结构在振动方面都是稳定的。然而，由于竞争相的吉布斯能量较低，Si 含量高的结构会分解。最后，使用SPS方法成功地合成了块体Ti 2 (Al 0.9 ，Si 0.1 )C。