Measurements of Young's modulus in the temperature range -150∼400°C and of rigidity modulus and hardness at room temperature have been made for Mn-Ni-Cr alloys subjected to various heat treatment and cold working conditions. The results indicate that the variation of Young's modulus with temperature for alloys which were slowly cooled after heating at 950°C for 1 hr shows an anomaly associated with the antiferromagnetic\rightleftarrowsparamagnetic transformation. The values of Young's modulus at room temperature for the alloys subjected to annealing are higher than those for the alloys subjected to cold working, water quenching or reheating after cold working or water quenching. Moreover, these values have a tendency to increase with increasing nickel or chromium content. As does with alloy composition, the temperature coefficient of Young's modulus differs greatly by the difference in treatment, viz. annealing, cold working, water quenching, and reheating after cold working or water quenching. A large maximum of positive sign is shown on the curves for the composition dependence of the temperature coefficient of Young's modulus, thus indicating the Elinvar property. The room-temperature rigidity modulus and its temperature coefficient show changes with composition, cold working and heat treatment. These changes are analogous to those for Young's modulus and its temperature coefficient. In general the hardness undergoes a complicated variation by alloy composition, cold working and heat treatment, the values being within the range of 100∼550 in Vickers hardness. Some of the ternary alloys have fairly high corrosion resistivity.
(Received December 15, 1972)
* This paper was presented at the 1970 Spring Meeting of the Japan Institute of Metals. Reported originally in Japanese in J. Japan Inst. Metals, 36 (1972), 881: The 62nd report from the Foundation: The Research Institute of Electric and Magnetic Alloys, Sendai, Japan.
** The Foundation: The Research Institute of Electric and Magnetic Alloys, 107, Higashi 8-bancho, Sendai, Japan.
© 2002 The Japan Institute of Metals
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