ON THE CRITICAL DEFORMATION OF ZR-NB ALLOYS WITH NB CONTENTS UP TO 2.5-PERCENT

The methods of metallographic analysis have been employed to study the dependence of the critical degree of deformation Ecr on the Nb content in cast Zr-Nb alloys with Nb contents up to 2.5% by mass. After compression testing at room temperature the grains with different orientations are deformed with different preferential mechanisms and degrees of deformation, as a result of the high anisotropy of the α-Zr crystalline lattice. Subsequent annealing develops this inhomogeneity and leads to the stabilization of structural differences. Consequently, recrystallized grains and deformed grains without recrystallization could be observed in the wide range of deformations applied. The conception of Ecr is in this case becomes somewhat diffuse. © 1990.