Study on the Effect of Y on the Morphology and Dispersion of TiB2 Particles in TiB2/Al Composites

Particle agglomeration and diversified particle morphologies are key technical issues that restrict the development of particle-reinforced composites. In this article, in situ TiB2/Al composites are prepared by the mixed salt reaction method, and the influence of rare-earth Y on the dispersion and morphological evolution of TiB2 particles is studied. In the results, it is shown that the in situ generated TiB2 particles are within the range of approximate to 474 +/- 210 nm in size. Upon the incorporation of 1.0Y, the TiB2 particles are refined to 352 +/- 83 nm. Through the microstructure analysis, it is shown that Y is covered on the TiB2 particles. Moreover, there is excellent interfacial wettability between the TiB2 particles and the aluminum matrix. The typical morphology of the TiB2 particles is hexagonal, and adding Y makes it tend to change to a spherical shape. Through first-principles calculations, it is shown that Y preferentially adsorbs on the {1120} and {1011} planes, hindering their growth, thereby changing the growth rate difference of the main crystal planes, ultimately resulting in the change of the TiB2 morphology. In this study, the regulatory mechanism of Y on TiB2 particles is elucidated, providing reference for the preparation and regulation of high-performance composites.