Numerical simulation of the B1 → B2 phase transformation in a potassium chloride sample when deformed in a gasket of a superhigh-pressure apparatus with diamond anvils

Abstract

The phase transformation process in a sample of polycrystalline potassium chloride KCl when deformed under quasihydrostatic conditions in diamond anvils of a superhigh-pressure apparatus has been numerically simulated. The stages of the transformation process have been studied and the process regularities found. The phase transformation in the volume of a finite element has been shown to result in an essential redistribution of the fields of plastic and volumetric strains as well as in a decrease of the pressure in the sample, force applied to anvils and, hence, a decrease of the motive force of the transformation. During the transformation several nuclei of the new phase form in a sample, which is caused by the plastic relaxation of stresses in the B1 elastoplastically deforming phase of KCl, i.e. the formation of a new nucleus becomes more preferable than the development of the old one.