Isothermal aging behavior of β Ti-Fe alloys

摘要

The isothermal aging behavior of Ti-5,8 and l0mass%Fe alloys at 673K, 723K and 773K was investigated by resistivity and hardness measurements, X-ray diffractometry and transmission electron microscopy. The Time-Temperature-Transformation diagramof the alloys was determined. In Ti-5 mass%Fe and Ti-8 mass%Fe, the isothermalω phase precipitated by aging at all of the aging temperatures. Because the isothermal ω phase did not precipitate by 773K aging in T-10mass%Fe, the upper temperature limitfor precipitation of isothermal ω phase in Ti-l0mass%Fe will situate between 723K and 773K. Incubation period prior to nucleation ofα phase is shortened with elevating aging temperature. The influence of Fe content on the time for nucleation of a phasewas not clear. Only at 723K, resistivity and hardness of all specimens show second abrupt decrease by more than 600ks aging, which suggests the precipitation of TiFe.