Iowa State University Research Foundation, Inc.

USA As Represented by Secretary of the Navy

Etrema Products, Inc.

O Dale McMasters

John D Verhoeven

Edwin D Gibson

Arthur E Clark

Frederick A Schmidt

Douglas K Finnemore

Jerome E Ostenson

Howard T Savage

Jonathan David Snodgrass

A high performance rare earth-transition metal magnetostrictive material with increased impurities having the formula (R,R,. . . R,),(M,M,. . . M,),is provided. Each R is selected from the group of elements consisting of lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, dysprosium, holmium, erbium and yttrium, where 0&lE;x,&lE;1, 0&lE;x,&lE;1 . . . 0&lE;x,&lE;1 and where x,&plus;x,&plus; . . . &plus;x,&equals;1. Each M is selected from the group of elements consisting of iron, manganese, cobalt, nickel, aluminum and silicon, where 0&lE;y,&lE;1, 0&lE;y,&lE;1 . . . 0&lE;y,&lE;1, where y,&plus;y,&plus; . . . &plus;y,&equals;1 and where 1.8&lE;z&lE;2.1. The material has oxygen impurities, nitrogen impurities and carbon impurities. The oxygen impurities having an atomic percent ranging from 6,011 to 34,000 parts per million. The nitrogen impurities having an atomic percent ranging from 575 to 4,400 parts per million. The carbon impurities having an atomic percent ranging from 939 to 21,000 parts per million. The material exhibits acceptable magnetostrictive strain performance at a reduced cost.

High performance rare earth-transition metal magnetostrictive materials

Magnetostrictive rods formed from rare earth-iron alloys are subjected to a short time heat treatment to increase their Magnetostrictive response under compression. The heat treatment is preferably carried out at a temperature of from 900.degree. to 1000.degree. C. for 20 minutes to six hours.

Thermal treatment for increasing magnetostrictive response of rare

This invention comprises a method of increasing the magnetostrictive response of rare earth-iron (RFe) magnetostrictive alloy rods by a thermal-magnetic treatment. The rod is heated to a temperature above its Curie temperature, viz. from 400.degree. to 600.degree. C.; and, while the rod is at that temperature, a magnetic field is directionally applied and maintained while the rod is cooled, at least below its Curie temperature.

Method of increasing magnetostrictive response of rare earth-iron alloy

The invention comprises a continuous casting and crystallization method for manufacturing grain-oriented magnetostrictive bodies. A magnetostrictive alloy is melted in a crucible having a bottom outlet. The melt is discharged through the bottom of the crucible and deposited in an elongated mold. Heat is removed from the deposited melt through the lower end portion of the mold to progressively solidify the melt. The solid-liquid interface of the melt moves directionally upwardly from the bottom to the top of the mold, to produce the axial grain orientation.

Continuous method for manufacturing grain-oriented magnetostrictive

Rods of magnetrostructive alloys of iron with rare earth elements are formed by flowing a body of rare earth-iron alloy in a crucible enclosed in a chamber maintained under an inert gas atmosphere, forcing such molten rare-earth-iron alloy into a hollow mold tube of refractory material positioned with its lower end portion within the molten body by means of a pressure differential between the chamber and mold tube and maintaining a portion of the molten alloy in the crucible extending to a level above the lower end of the mold tube so that solid particles of higher melting impurities present in the alloy collect at the surface of the molten body and remain within the crucible as the rod is formed in the mold tube.

Method of forming magnetostrictive rods from rare earth-iron alloys

Grain-oriented polycrystalline or single crystal magnetostrictive materials n the general formula Tb.sub.x Dy.sub.1-x Fe.sub.2-w, Tb.sub.x Ho.sub.1-x Fe.sub.2-w, Sm.sub.x Dy.sub.1-x Fe.sub.x-w, Sm.sub.x Ho.sub.1-x Fe.sub.2-w, Tb.sub.x Ho.sub.y Dy.sub.z Fe.sub.2-w, or Sm.sub.x Ho.sub.y Dy.sub.z Fe.sub.2-w, wherein O.ltoreq.w.ltoreq.0.20, and x+y+z=1. X, y, and z are selected to maximize the magnetostrictive effect and the magnetomechanical coupling coefficient K.sub.33. These material may be used in magnetostrictive transducers, delay lines, variable frequency resonators, and filters.

Growing community of inventors

Ames, IA, United States of America

O Dale McMasters