Effect of cold rolling on the thermal expansion and magnetic properties of Fe-B amorphous invar alloys

Fe-B amorphous Invar alloys prepared from the melts were cold-rolled along the ribbon direction. The thermal expansion coefficient measured parallel to the ribbon direction at room temperature depends on the rolling reduction ratio and the boron concentration. The coefficient of Fe83B17alloy decreases linearly and that of Fe86B14alloy increases gradually. The high-field susceptibility measured along the same direction at 4.2 K increases with increasing the cold-rolling ratio. These results suggest that the number of Fe-Fe pairs along the ribbon direction is increased by cold-rolling.