Age-hardening behaviour of two metastable beta-titanium alloys

作者：Ng H P^*; Douguet E; Bettles C J; Muddle B C

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2010, 527(26): 7017-7026.

DOI：10.1016/j.msea.2010.07.055

• Titanium alloys
• Quench-rate sensitivity
• Age hardening
• Electron microscopy

Two novel beta-titanium alloys, of compositions Ti-10V-2Ni and Ti-10V-6Cu (wt.%) and with distinct potential for athermal omega-phase formation, have been selected and the sensitivity of the age-hardening responses to the cooling rate post solution treatment investigated. Upon rapid water quenching, the solution-treated Ti-10V-2Ni alloy contained a significantly higher volume fraction of omega-phase than the Ti-10V-6Cu alloy. It was observed that the Ti-10V-6Cu alloy is remarkably insensitive to cooling rates in the range of water quenching to air cooling, in terms of both microstructural evolution and age-hardening behaviour, when aged isothermally at 350 degrees C and 500 degrees C. The microstructure is thermally stable and the hardness remains approximately constant for extended aging (48 h) at both temperatures, implying that it may have potential as a deep-hardenable alloy. In comparison, the aging response of the Ti-10V-2Ni alloy was marginally influenced by cooling rate when aged at 500 degrees C, the effect being ascribed to auto-catalytic formation of alpha-phase in the course of slow air cooling. The results are discussed with respect to the beta-phase stability and the time-temperature-transformation (TIT) characteristics of metastable beta-titanium alloys.

• 出版日期2010-10-15