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 <11 2 ¯ 0>α2//[010]B27 and (0001)α2//(001)B27. The Burgers alpha variants were inoculated by the boride precipitates having an OR with beta phase and the OR was deduced as (001)TiB//{110}β, (010)TiB//{111}β and (100)TiB//{211}β.