Deformation twinning and the Hall-Petch relation in commercial purity Ti

The effect of grain size and deformation temperature on the behavior of wire-drawn alpha-Ti during compression has been examined. At strains of 0.3, the flow stress exhibited a negative Hall-Petch slope. This is proposed to result from the prevalence of twinning during the compressive deformation. Electron backscattered diffraction revealed that {10 (1) over bar2}was the most prolific twin type across all the deformation temperatures and grain sizes examined. Of the twinning modes observed, {11 (2) over bar2} twinning was the most sensitive to the grain size and deformation temperature. The range of morphologies exhibited by deformation twins is also described.