Abstract
Effects of annealing, hydriding-dehydriding cycles and particle size on hydrogen storage properties of FeTi have been studied by measuring the pressure-composition-temperature relations. The equilibrium pressure for the formation of the γ hydride phase in the as-cast specimen was lower than that in the annealed specimen. It can be explained in terms of the heterogeniety of composition due to imcompleteness of the peritectic reaction. The equilibrium pressure for the formation of the γ phase increased with increasing hydriding-dehydriding cycles. This is considered to be due to hardening caused by the high density of dislocations which are generated during the cycles. The activation for hydriding became difficult and the dissociation pressure of the β and γ phases increased with increasing particle size.
