Nonmagnetic Elinvar-Type Alloys in the Mn–Ni System

modulus at room temperature was almost independent of cold working and heat treatment except for a large difference between the γ and the mixture phases on the Mn side. A remarkable minimum in Young's modulus. was also observed near 18.50% nickel. The temperature coefficient of Young's modulus at room temperature depends largely on the heat treatment, cold working and alloy composition. When it is plotted as a function of composition, it exhibits a large maximum of positive sign and a minimum of negative sign. The highest positive temperature coefficient of the Young's modulus in the annealed state is +119.50×10-5 for the alloy containing 20.30% Ni, thus exhibiting the Elinvar property. The rigidity modulus also exhibits a similar behavior. The values of hardness in the annealed, water quenched and reheated states were generally lower than that in the cold worked and reheated states. (Received November 30, 1971)