Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Nonmagnetic Elinvar-Type Alloys in the Mn-Cu System
Hakaru MasumotoShôhachi SawayaMichio Kikuchi
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1971 Volume 35 Issue 7 Pages 723-730

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Abstract

Measurements of Young’s modulus and thermal expansion at −150°∼400°C and of rigidity modulus and hardness at room temperature have been carried out with Mn-Cu alloys subjected to a variety of heat treatment and cold working. It is shown that Mn-Cu alloys containing 6.00∼57.46%Cu slow-cooled after heating for 1 hr at temperatures below 80°C from the melting points have distinct antiferromagnetic Néel points in the thermal expansion and Young’s modulus temperature curves, revealing Elinvar property. The values of Young’s modulus in annealed state were higher than those in the cold-worked or the water-quenched state, the difference being remakably large in the (α+γ) phase on the Mn side. The hardness of Mn-13∼17%Cu alloys was very high regardless of the heat treatments involved. The temperature coefficient of Young’s modulus undergo a wide variation with annealing, water-quenching, cold-working, and reheating after water-quenching or cold-working, and also with alloy composition.
The curves of temperature coefficient of Young’s modulus vs. composition generally have large maxima and minima in positive and negative signs, thus indicating the Elinvar property. The highest positive temperature coefficient of Young’s modulus in the annealed state was 14.7×10−5 for the composition of 56.40%Cu. Further, the changes in rigidity modulus and its temperature coefficient with heat treatment, cold working and composition bear a close resemblance to those in Young’s modulus and its temperature coefficient.

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