Ni-Cu系合金のヤング弾性率と結晶粒度

Abstract

The Young’s modulus and the grain size have been measured with 10 kinds of polycrystalline ferromagnetic Ni-Cu alloys annealed at 700°, 800°, 900°, 1000° and 1100°. The following empirical relation between the Young’s modulus E and the average area of crystal grains S has been found: \[E=E0−BlogS\] where E0 and B are constants. The Young’s modulus vs. composition curves for alloys with the same grain size are not always similar to each other but each curve shows a minimum. The composition corresponding to the minimum shifts to the nickel side as the grain size becomes larger. With an addition of copper, the Young’s modulus of nickel with comparatively smaller grains increases, and that with comparatively larger grains decrases. These results suggest that the complexity of the so-far observed Young’s modulus vs. composition curves for Ni-Cu alloys may partly be due to the difference in the grain size of the individual alloy specimens. Finally the measured results are compared with that calculated from the formula derived by Voigt and Reuss.