Microstructure evolution of Zr alloy during hot deformation

Grain refinement using hot deformation has an industrial importance for the processing of Zr alloys. The processing map for Zr alloys was developed earlier to identify the optimum hot working parameters and this established condition has been used in the current study. This condition in general exhibit dynamic recrystallization (DRX). DRX during hot deformation leads to better stability and superior mechanical properties of the alloy. To study the evolution of DRX grains in Zr, the samples were uniaxially compressed at 800 °C, 0.1 s^-1 using GLEEBLE 3800 thermo-mechanical simulator up to various strain levels. Samples were quenched immediately after deformation to retain the hot deformed microstructure. Microstructure and texture of the samples were investigated using EBSD on the longitudinally sectioned faces. A detailed analysis using KAM, GAM and GOS was done to identify the nucleating sites for the daughter grains. Stored energy was calculated for the parent grains to identify the orientations preferable for DRX grain formation. Analysis revealed the formation of DRX grains along the boundaries of the deformed parent grains. (author)