High temperature compression of Ti3Al-Nb-V-Mo alloy

Samples of Ti-24Al-14Nb-3V-0.5Mo alloy were hot compressed in the α₂ + β phase field. It was found that Ti-24Al-14Nb-3V-0.5Mo alloy has good hot workability and no cracks were found on the billet surfaces. The compression flow stress varied from 13 MPa to 128 MPa over the range of conditions used. The compression pressure required for deformation is strongly dependent on temperature and strain rate. The experimental results show that hot compression can be applied satisfactorily to deform the Ti-24Al-14Nb-3V-0.5Mo alloy within temperature and strain rate ranges of 1030-1130°C and 0.001-0.1 s^-1 to about 50% height reduction. A strain rate sensitivity exponent m of 0.263 and a deformation activation energy of 621 kJ mol^-1 were obtained for the compression conditions used and it is considered that the deformation mechanism of Ti-24Al-14Nb-3V-0.5Mo alloy in the α₂ + β phase field involves a combination of dynamic recovery and grain boundary sliding. An empirical power law equation valid over the range of temperatures and strain rates investigated was developed. The equation describes accurately the dependence on temperature and strain rate of the flow stress.