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.

Interface Alloying Design to Improve the Dispersion of TiB2 Nanoparticles in Al Composites: A First-Principles Study

“…Herein, our calculated result provides a direct theoretical verification for their experimental results. Similarly, the improvement of Ce on the Al/TiB 2 interface ability agrees with the view of Xue et al Combining DFT calculation with experiment observation, they found that the absorption of the Ce element on the Al/TiB 2 interface can promote the dispersion of TiB 2 particles via reducing the interfacial energy. Conclusively, Ce should be the proper element for the dispersion of TiB 2 particles.…”

“…Similarly, for TM elements, the Sc of 3d-TM, Y, Zr, Pd, and Ag of 4d-TM, and Ce, Hf, Pt, and Au of 5d-TM elements can reduce the interface energy of the Al(111)/TiB 2 (0001) interface, while others can elevate the interface energy. The identical alloying effect of the Ce element is also reported by Xue et al 49 Moreover, the variation of Δγ int values about the atomic number of TM elements in the same period follows a convex-down parabolic-like tendency. An analogous alloying phenomenon also can be seen in the grain boundary of aluminum.…”

“…To improve the degree of the dispersion of TiB 2 particles in Al matrix composites, alloying addition is a simple and effective method. According to experimental research, several elements have shown the positive alloying effect, such as Mg, 19 Ce, 49 and Sc. 53 Although their influence levels are different, they are difficult to compare due to different experimental environments.…”

Effects of Sc on the microstructure and properties of in situ ZrB2/7085Al composites

“…Rare earth Sc had a huge impact on the size of particle clusters, the number of clusters, and the size of ZrB 2 nanoparticles. On the other hand, the solid solubility of Sc atoms in Al matrix was low, led to rare earth Sc was easily adsorbed on the phase and grain boundaries, which filled up the interface defects and reduced the interface energy between ZrB 2 and Al matrix [33]. Rare-earth element Sc had a great effect on inhibiting particle agglomeration.…”