Magnetostriction of single crystal and polycrystalline Tb0.60Dy0.40 at cryogenic temperatures
Abstract
At cryogenic temperatures, single crystals of TbDy alloys exhibit giant magnetostrictions of nearly 9000 ppm, making these materials promising for engineering service in cryogenic actuators, valves, and positioners. The preparation of single crystals is difficult and costly. Preliminary results on the magnetostriction of textured polycrystalline materials are presented here. For instance, polycrystalline Tb0.60Dy0.40, plane-rolled (one direction of applied stress) to induce crystallographic texture, has shown magnetostrictions at 77 K of 3000 ppm for an applied field of 4.5 kOe and an applied load of 23 MPa, or 48% that of a single crystal under similar conditions. Comparisons are presented between the magnetostrictive response of plane- and form-rolled (two orthogonal directions of applied stress) polycrystalline Tb0.60Dy0.40 at 10 and 77 K. It is reported that at 10 K plane-rolled Tb0.60Dy0.40 exhibits 1600 ppm magnetostriction at an applied field of 4.4 kOe with a minimal applied load of 0.28 MPa. An observed restoration of the initial unstrained state may be a useful feature of polycrystalline materials for engineering service. Finally it is reported that thermal expansion measurements provide a measure of crystallographic texture for comparison with the magnetostriction.
Additional Information
© 1999 American Institute of Physics. The research described in this article was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration and at the California Institute of Technology. This work was supported under the Advanced Technology Development program with funds provided by the Microgravity Division. The single crystals were kindly furnished by Dr. M. Wun-Fogle of the Naval Surface Warfare Center in Silver Springs, MD. The authors are indebted to Dr. A. E. Clark for many helpful discussions. The single crystal and arc melted ingots were prepared by Dr. T. Lograsso at Ames Laboratory.Attached Files
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2006-04-12Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field