CeO₂ induced dispersive distribution of TiB₂ particles in in situ TiB₂/Al composite

Abstract

The roles of CeO₂ additive during preparation of in situ TiB₂/Al composite, alleviating particle settlement in composite melt and significantly improving particle dispersion in final microstructure, are studied in this paper. It is evidenced that the CeO₂ additive reacts with Al melts to release Ce solute into the melts, and the released surface active Ce is absorbed in the Al/TiB₂ interfaces without any other reaction products. First principles calculations show that the interfacial energy of Al/TiB₂ interfaces is reduced owing to the presence of Ce in Al/TiB₂ interfacial area. Therefore, the wettability of molten Al on TiB₂ surface is increased and the dispersion of TiB₂ particles in Al matrix is eventually improved.

Keywords:

• Metal matrix composites
• Dispersion
• Interface
• First principles interfacial energy calculations

Acknowledgments

The authors wish to acknowledge the support of the National Natural Science Foundation of China (grant nos. 51001074 and 51274141) and National High Technology Research and Development Program of China (863 project) (grant no. 2008AA03A239). At the same time, the authors are grateful to the Instrumental Analysis Center of Shanghai Jiao Tong University for help in microstructure analysis.