EFFECT OF ANNEALING TEMPERATURE ON THE EVOLUTION OF THE DISLOCATION AND DOMAIN STRUCTURE OF Pd3Fe ALLOY IN DISORDERED AND ORDERED STATES

10.25712/ASTU.1811-1416.2022.01.007

Abstract

The paper presents studies of the dislocation and domain structure of ordered and disordered polycrystalline Pd₃Fe alloy. To study the defect structure, the method of electron diffraction microscopy was used. The ordered state of the alloy was achieved by stepwise cooling of the samples at a rate of 5 and 10 degrees per day at different annealing temperatures. An increase in the annealing temperature and cooling rate affects the size of the domains that form in the alloy. The types of dislocation substructures (DSS) change with an increase in the degree of deformation ε. In an ordered alloy and in a disordered one, at the same degree of deformation, the types of dislocation substructure are somewhat different. The main parameter characterizing the hardening of a material is the average scalar density of dislocations. The dislocation density increases with an increase in the degree of deformation and a fixed annealing temperature. With an increase in the degree of deformation, misorientations are formed in the structure. Misorientations are qualitatively identified by the appearance of extinction deformation contours on electron microscopic images. The quantitative parameter of the disordered structure is the curvature-torsion of the crystal lattice (χ). It has been established that the value of χ increases with an increase in the degree of deformation.