Analysis of the role of plastic deformation on the transformation kinetics of the metastable β-Cez titanium alloy

摘要

The effect of a plastic deformation on the β―α transformations of the β-Cez has been studied for transformation temperatures ranging from 830 to 600°C. Applying a deformation in the metastable β range leaded to an accelerated isothermal transformation kinetics. The effect of the deformation is essentially to modify the nucleation rate of the grain boundary α phase. This accelerating effect is larger for deformation temperatures close to the transformation temperatures, and for the lowest undercoolings. In isothermal transformation conditions the α_(WGB) width remains constant indicating that the growth rate is nearly unaffected. For intragranular α phase, the nucleation rate is also increased. In consequence the aspect ratio (width/length) of the α phase is increased. In the case of transformation during continuous cooling, the previous deformation strongly accelerates the β-> α_(GB) -> α_(WGB) transformation.