Magnetic Properties in the Cold-Worked State of Iron-Nickel-Chromium Alloys Containing 35 wt%Ni and 0∼20 wt%Cr

Abstract

In succession to the measurements of the strain gauge factors and electrical resistivities reported in the preceding paper, the saturation magnetization, Curie temperature and magnetostriction have been measured in the cold-worked state of iron-nickel-chromium alloys containing 35 wt%Ni and 0∼20 wt%Cr. The Curie temperature does not show any substantial change with the chromium content up to about 7%, beyond which it shows a rapid decrease. Contrary to this, the saturation magnetization decreases almost linearly with increasing chromium content. The forced magnetostriction coefficient decreases appreciably with increasing chromium content up to about 7%Cr, then remains almost constant up to 14.3 wt%Cr, and finally drops to zero at 18.46%Cr, where the alloy is paramagnetic at room temperature. Whereas, the saturation magnetostriction shows a monotonous decrease with increasing chromium content. From the above finding the largest value of the strain gauge factor obtained at about 7%Cr appears to be related to the composition dependence of the Curie temperature, forced magnetostriction coefficient and electrical resistivity as described in the preceding paper. It is shown that the high strain gauge factors in this ternary alloy system can be interpreted thermodynamically.