Effect of heat treatment and exposure on microstructure and mechanical properties of Ti–25V–15Cr–2Al–0.2C (wt%) Original Research Article

The effect of heat treatment and exposure on the microstructure and mechanical properties of extruded, burn-resistant β titanium alloy Ti–25V–15Cr–2Al–0.2C (wt%) has been studied. It has been found that pre-exposure annealing at 600, 700 and 800°C affected the distribution of α phase that precipitated following subsequent exposure at temperatures between 450 and 550°C. Samples annealed at 600°C and subsequently exposed at 450°C showed excellent microstructural and property stability. Although the room-temperature ductility of the alloy decreased and the strength increased slightly with increasing exposure time at 500°C, no further drop in ductility was observed after 500 h. However, a gradual degradation of properties with exposure time was observed in samples exposed at 550°C. The significance of the observations is discussed in terms of the effect of pre-exposure annealing and exposure on α precipitation and tensile properties.