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The effect of strain-path reversal on the kinetics of dynamic spheroidization during subtransus hot working was determined for Ti-6Al-4V with a colony ␣ structure. Isothermal torsion tests were conducted at a temperature of 815°C and a strain rate of 0.001 s Ϫ1 ; strain-path reversals were achieved by applying forward and reverse torsion sequentially. The kinetics of spheroidization were measured as a function of the local (macroscopic) strain for monotonic-deformation, reversed-torsion, and double-reversed-torsion tests. Strain-path reversal led to a reduction in the spheroidization kinetics compared with monotonic deformation for a given total strain. The slower rate of dynamic spheroidization associated with strainpath reversals was ascribed to a reduced rate of sub-boundary formation/lower sub-boundary energies, which drive the boundary splitting process, and less sharp ␣/␤ interface curvatures, which control the coarsening process that also contributes to spheroidization.

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The finishing rolling of microalloyed steels was simulated by double-deformation plane strain compression testing of both model and conventional steels microalloyed with Nb. The flow behavior following interpass delay times of 1-100s was related to the deformed microstructure, the deformation substructure and the strain-induced precipitation. Fe-30wt%Ni is clearly a good model alloy for conventional microalloyed steels, as similar results are observed for both materials. In addition, the location of fine strain-induced precipitates in relation to the deformation substructure can be determined directly using transmission electron microscopy.

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