In this paper, medium-entropy metal diboride (Ti1/3Cr1/3V1/3)B2 with a hexagonal TiB2-type crystal structure were synthesized via molten salt reaction, and its effect on refining pure aluminum grains was investigated. Compared with TiB2, the minimum lattice mismatch between Al and (Ti1/3Cr1/3V1/3)B2 is reduced from 5.6% to 3.7%, effectively reducing undercooling required for nucleation. By just adding 1.5 vol% (Ti1/3Cr1/3V1/3)B2, the average grain size of commercial pure aluminum is reduced to ∼32 μm. The synthesized particles are expected to be used in grain refinement during additive manufacturing and rapid solidification, and in the preparation of aluminum matrix composites. This study opens up a new direction in designing new compounds for grain refinement by tailoring lattice matching within multi-component composition space.
Citation
Xiao, F., Wu, M., Wang, Y., Wang, S., Shu, D., Wang, D., Zhu, G., Mi, J., & Sun, B. (2022). Design of newly effective grain refiner for aluminum based on medium-entropy metal diboride. Vacuum, 205, Article 111462. https://doi.org/10.1016/j.vacuum.2022.111462
