PHASE TRANSFORMATION TRIGGERED BY EXTERNAL LOADING IN POLYCRYSTALLINE Cr-DOPED V₂O₃

Abstract
Cr doped V₂O₃ exhibits a phase transformation near ambient temperature. Because of internal stresses in sintered polycrystals a significant undercooling must be reached in order to first transform the material from the high to the low temperature phase (with the formation of microcracks). It is shown that the phase transformation can be triggered locally by superimposing an applied load by means of a spherical indenter to the unknown internal stress field in slightly undercooled materials. Depending upon the intensity of the local stress the structure and extent of the damaged zone below the indented surface can be varied and have been investigated. A tentative rationalization of the results is given in terms of a thermodynamic energy balance calculation.