Evaluation of Mechanical Properties for Spherical Magnetic Regenerator Materials Fabricated by Rapid Solidification Process
Various magnetic regenerator materials, such as Er3Ni, Er3Co and ErNi, are fabricated in the form of a spherical particle by a rapid solidification process. 4 K level refrigeration has been obtained by a GM refrigerator using these materials. However, the magnetic regenerator materials are considered brittle, as they are intermetallic compounds.
It is important to evaluate the mechanical properties of these materials to confirm reliability as a regenerator material. In this paper, experimental results of compression and vibration tests for magnetic regenerator materials are described. The technical point of this study is to use spherical particles as test samples.
The compressive stress of 20 MPa was applied to these spherical particles and no fractured spheres were observed. Similarly, no fractured spheres were found after the vibration test, in which the maximum acceleration was 30 × 9.8 m/s2 and the number of vibration times was 1 × 106, insofar as there was no room to stir spherical particles in a regenerator.
In practice, the reliability of magnetic regenerator materials has been confirmed by a long-run test of 7, 000 h in a usual GM refrigerator.
KeywordsCompressive Stress Intermetallic Compound Spherical Particle Maximum Acceleration Vibration Test
Unable to display preview. Download preview PDF.
- 1.M. Sahashi, Y. Tokai, T. Kuriyama, and H. Nakagome, New magnetic material R3T system with extremely large heat capacities used as heat regenerators, Adv.in Cryo.Eng., 35B: 1175(1990).Google Scholar
- 4.T. Kuriyama, R. Hakamada, H. Nakagome, Y. Tokai, M. Sahashi R. Li, O. Yoshida, K. Matsumoto, and T. Hashimoto, High efficient two-stage GM refrigerator with magnetic material in the liquid helium temperature region, Adv.in Cryo.Eng., 35B: 1261 (1990).Google Scholar
- 5.M. Nagao, T. Inaguchi, H. Yoshimura, T. Yamada, and M. Iwamoto, Helium Liquefaction by a Gifford-McMahon cycle cryocooler, Adv. in Cryo.Eng., 35B: 1251(1990).Google Scholar