Isothermal phase transformations and age hardening of rapidly solidified Ti-24Al-11Nb
- Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering
Time-temperature-transformation behavior of a rapidly solidified (RS) Ti-24Al-11Nb alloy was studied over the temperature range of 500 and 700 C. Age-hardening was found to occur during the stage of B2 (ordered bcc) {r_arrow} O (ordered orthorhombic) transition. The hardness increased to a maximum value ({approximately}5.4 Gpa) as the sample contained mostly the lath-like O phase. Further aging resulted in a softening to the alloy when the lath-like O phase started to coalesce and preceded by the O {r_arrow} {alpha}{sub 2} transition. The hardness decreased to a minimum value ({approximately}2.6 GPa) when the alloy contained mostly equiaxed {alpha}{sub 2} grains. The results showed that there exists a critical temperature ({approximately}500 C), below which the O {r_arrow}{sub 2} transition was very sluggish. Accordingly, the O phase became stable when the RS Ti-24Al-11Nb alloy was aged below the critical temperature.
- OSTI ID:
- 72420
- Report Number(s):
- CONF-9310224--; ISBN 0-87339-249-3
- Country of Publication:
- United States
- Language:
- English
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