Effects of thermal cycling on visco-elastic properties of solution-treated aged and stress relief annealed Ti-6Al-4V alloy

The present work deals with the changes in the viscoelastic properties of Ti-6Al-4 V alloys subjected to heat treatments and a novel thermal cycling procedure. As titanium is widely used in the automotive industry, its storage modulus and damping effect have been a significant concern for many industries. The visco-elastic property of heat-treated alloy has been recorded using dynamic mechanical analysis. Scanning Electron Microscopy analysis results showed that the bimodal phases and fine needlelike martensite were obtained in clustered form in solution-treated aged and thermally cycled samples. However, martensite was not observed in stress relief annealed heat treatment and thermally cycled samples. Storage modulus was found to be increased in samples with the formation of α' martensite. The storage modulus of the stress relief annealing samples and solution-treated aged samples at 1000 cycles exceeded the 80,000 MPa, which is not the case for the base metal at 1000 cycles without any heat treatment. Moreover, at 1000 cycles, the solution treatment and aging process show a 25.9% – 25% decrease in damping capacity when compared to base metal and a 11.3% – 7.7% decrease in damping capacity when compared to the stress relief annealing process, over the temperature range of 0°C – 250°C.