Fe-Pd系合金の熱膨張係数と弾性係数の温度係数

抄録

The density ρ, Young’s modulus E, the thermal expansion coefficient α, and the temperature cofficient of Young’s modulus e were measured with the alloys of iron and palladium cooled in a furnace after having been annealed at 1000°C to asscertain whether the rule on the small expansibility of Invar proposed previously by one of the present investigators is valid in the above alloy system or not. It was found that both the curves of ρ and of E against the alloying concentration show respectively, slight bends at the composition of 30 at.% of palladium, and also α shows its minimum value of +8.9×10⁻⁶ and e its conspicuous positive maximum value of +139.9×10⁻⁵ at the composition mentioned above. The alloy containing 30 at.% of palladium is composed almost of γ phase after a furnace cooling, but when it was cooled more slowly than 30°C/hr from 800°C, the amount of the γ phase decreased. It was 0 at the cooling rate of 5°/hr, and an increase of α to +12.3×10⁻⁶ and a decrease of e to −12.5×10⁻⁵ resulted, both of these magnitudes being of the order of usual alloys. According to these results, it can be confirmed that the rule on Invar mentioned above can also be valid in the system of iron and palladium under all the conditions.