The phase diagram of Ti-6Al-4V at high-pressures and high-temperatures
- AWE, Reading (United Kingdom); Univ. of Edinburgh, Scotland (United Kingdom). SUPA, School of Physics and Astronomy, and Center for Science at Extreme Conditions
- Univ. of Valencia (Spain). Departmento de Física Aplicada-ICMUV
- AWE, Reading (United Kingdom)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Diamond Light Source, Ltd., Oxfordshire (United Kingdom). Harwell Science & Innovation Campus
- Univ. of Edinburgh, Scotland (United Kingdom). SUPA, School of Physics and Astronomy, and Center for Science at Extreme Conditions
- CELLS-ALBA Synchrotron Light Facility, Barcelona (Spain)
We report results from a series of diamond-anvil-cell synchrotron x-ray diffraction and large-volume-press experiments, and calculations, to investigate the phase diagram of commercial polycrystalline high-strength Ti-6Al-4V alloy in pressure–temperature space. Up to ~30 GPa and 886 K, Ti-6Al-4V is found to be stable in the hexagonal-close-packed, or α phase. The effect of temperature on the volume expansion and compressibility of α–Ti-6Al-4V is modest. The martensitic α → ω (hexagonal) transition occurs at ~30 GPa, with both phases coexisting until at ~38–40 GPa the transition to the ω phase is completed. Between 300 K and 844 K the α → ω transition appears to be independent of temperature. ω–Ti-6Al-4V is stable to ~91 GPa and 844 K, the highest combined pressure and temperature reached in these experiments. Pressure–volume–temperature equations-of-state for the α and ω phases of Ti-6Al-4V are generated and found to be similar to pure Ti. A pronounced hysteresis is observed in the ω–Ti-6Al-4V on decompression, with the hexagonal structure reverting back to the α phase at pressures below ~9 GPa at room temperature, and at a higher pressure at elevated temperatures. Based on our data, we estimate the Ti-6Al-4V α–β–ω triple point to occur at ~900 K and 30 GPa, in good agreement with our calculations.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1781304
- Report Number(s):
- LLNL-JRNL-818928; 1029735; TRN: US2209902
- Journal Information:
- Journal of Physics. Condensed Matter, Vol. 33, Issue 15; ISSN 0953-8984
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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