Synthesis of nanoscale spherical TiB_2 particles in Al matrix by regulating Sc contents

摘要

In situ TiB2 particles with polyhedral or near-spherical morphology with more high-index crystal planes exposed were prepared by controlling the addition amount of Sc in commercial pure aluminum matrix. As the content of Sc increased, TiB2 morphology transformed from hexagonal platelets to polyhedral or near-spherical morphology with a decrease in particle size. In the present paper, a simple method to prepare near-spherical in situ TiB2 particles in Al matrix was explored and it was found that the reinforcement distribution was improved significantly. The different growth mechanism of TiB2 particles in Al and Al-Sc systems was discussed. The key reason for the morphology evolution was that the Sc was preferentially adsorbed on {1 (2) over bar 12}, {11 (2) over bar0}, and {10 (1) over bar1} which would inhibit the growth of these faces effectively and retain a lower-energy state of the polyhedral or quasispherical TiB2 particles in Al-Sc systems.