Pressure-Induced Reverse Martensitic Transition in Fe<SUB>0.7</SUB>Ni<SUB>0.3</SUB>

Abstract

An alloy Fe 0.7 NI 0.3 has been studied under high pressure up to 45 GPa by X-ray diffraction and an electric resistance measurement. The bcc α'-martensitic phase is transformed to a fcc y-austenitic phase at 8 GPa at room temperature. This transition is accompanied by the volume reduction of 0. 17x1O -6 m 3 /mol and a large resistance increase. The decrease of the austenite-start temperature, A s , from 623 K at ambient pressure to room temperature at 8 GPa gives the mean value of dA s /dP=-40.4 K/GPa