Grain refinement in beta-solidifying Ti44Al8Nb1B

作者：Hu D^*; Yang C; Huang A; Dixon M; Hecht U

来源：Intermetallics, 2012, 23: 49-56.

DOI：10.1016/j.intermet.2011.12.022

• Titanium aluminides, based on TiAl
• Phase identification
• Phase transformation
• Crystal growth
• Microstructure

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 %26lt;11%26lt;(2)over bar%26gt;0%26gt;(alpha 2)//[010](B27) and (0001)(alpha 2)//(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)(beta), (010)(TiB)//{111)(beta) and (100)(TiB)//{211}(beta).

• 出版日期2012-4