Etude de la déformation plastique de monocristaux de niobium de haute pureté a basse température

Abstract

Plastic deformation of single crystals of niobium

Tensile tests have been performed on high purity niobium single crystals between 2.17 and 300 K. Yield stresses, activation volumes and energies and dislocation structures have been investigated.

It seems that three different deformation mechanisms are operating, each of them in a definite temperature range. At the lower temperatures very simple experimental laws have been found. These experimental results have been compared to the existing models for the yield stress of b.c.c. metals.