Grain refinement in beta-solidifying Ti44Al8Nb1B

Grain refinement in Ti44Al8Nb1B was studied using directional solidification technique and SEM EBSD analysis. Grain refinement occurred during beta-to-alpha transformation through boride assisted alpha nucleation mechanism rather than during solidification. Burgers and non-Burgers alpha2 grain coexisted and they were inoculated by boride precipitates. The orientation relationship between alpha and the B27 TiB precipitates is <112¯0>α2//[010]B27...