High temperature tensile deformation behavior of β-Ti alloys

Abstract

The high temperature tensile deformation behavior of β-Ti alloys has been investigated as function of strain rate, temperature and type of alloying elements. It was found that the magnitude of the flow stress drop increases with strain rate and solute concentration and decreases with temperature. For a given temperature and strain rate the extent of the drop decreased with a decrease in the relative atomic size between the solvent (titanium) and solute (manganese and vanadium) and a decrease in the diffusivity of the alloying element in the β phase. In addition, it was found that prestraining to a stress below the peak stress significantly reduces the peak stress and the magnitude of the flow stress drop. On the basis of these results it is suggested that the initial flow stress drop is due to the rapid multiplication of dislocations. The steady state behavior after the initial flow stress drop was attributed to dynamic recovery leading to the formation of subgrains.