A study of phase transformation in a TiAlNb alloy and the effect of Cr addition

作者：Kesler Michael S; Goyel Sonalika; Rios Orlando; Cupid Damian M; Seifert Hans J; Ebrahimi Fereshteh^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2010, 527(12): 2857-2863.

DOI：10.1016/j.msea.2009.12.046

• TiAlNb system
• Phase transformation
• Titanium aluminides
• Cr addition
• Sigma phase

The phase transformation paths, transformation temperatures and phase equilibria of Ti-45Al-27Nb and Ti-45Al-22Nb-5Cr (at%) alloys were evaluated over a temperature range from 865 degrees C to 1600 degrees C. Both alloys solidified as single beta-phase and transformed to gamma + sigma phases upon slow cooling. The addition of Cr did not affect the beta -> gamma transformation temperature upon slow cooling. In contrast, the temperature, at which the sigma-phase formed, was reduced noticeably. Upon heating, the temperature at which the beta-phase evolves from the gamma + sigma microstructure was found to decrease significantly with the addition of Cr. In the ternary alloy the formation of the gamma-phase could not be retarded on quenching, however, the substitution of Nb with Cr allowed for the retainment of the beta-phase to room temperature. These results are explained by the partitioning of Cr into the beta-phase, which in addition to thermodynamic stability reduces the kinetics of transformations at lower temperatures.

• 出版日期2010-5-15
• 单位中国矿业大学（北京）