Effects of Initial Strains on the Pressure Dependence of Lattice Constants on Some Iron Group Metals and Alloys

Abstract

The pressure dependence of the lattice constant was observed up to about 30 kbar with a solid pressure-medium using the powder X-ray diffraction method for some Ni- and Fe- based alloys. An anomalous behavior, a bulge, in the lattice constant versus pressure curve was observed in the low pressure region for every specimen with initial internal strains and the bulge vanished with annealing of the specimen. The bulge was observed when the specimen in the ferromagnetic state with nonzero magnetostriction constants had an initial strain before pressurization. A nonhydrostatic component of pressure inherent in the solid pressure medium also seems to play an important role in the appearance of the bulge.