Structure of Dislocations and Mechanical Properties of B2 Alloys

Abstract

ABSTRACTAdequate mechanical properties are important for both structural and functional applications of materials. There are significant differences in mechanical behaviour of different B2 ordered alloys and these are related to the properties of superlattice dislocations. Several types of dislocations can be activated, in particular <111> and <001> dislocations gliding on {110} planes. Their mobility can vary markedly from material to material and this has a strong impact on the mechanical properties. With the aim to elucidate qualitatively the differences between different alloys crystallising in the same B2 structure we analyse possible dislocation dissociations. The model employed is based on the isotropic elasticity but includes an important characteristic of stacking-fault-like defects involved in the splittings, the deviation of their displacements away from the usually assumed ½<111> APB.