At&t Bell Laboratories

At&t Technologies, Inc.

Chester M Boredelon

Richard C Sherwood

Sungho Jin

Gilbert Y Chin

Jack H Wernick

Disclosed are magnetically soft ferritic multiphase Fe-Cr-Ni alloys containing at least about 82 weight percent Fe, between about 3 and about 10 weight percent Cr, and between about 2 and about 8 weight percent Ni, a method for producing such alloys, and devices comprising such an alloy body. The method comprises a low-temperature anneal in the (.alpha.+.gamma.) region of the Fe-Cr-Ni phase diagram. Inventive alloys typically have a coercive force H.sub.c no more than about 3.0 Oe, preferably no more than about 2.0 Oe, a maximum permeability .mu..sub.m of at least about 1500 G/Oe, preferably at least about 2500 G/Oe, and contain at least about 5 volume percent non-.alpha.-phase material, typically .alpha.'- and .gamma.-phase material. Inventive alloys typically also have yield strength to 0.2% offset of at least about 26.10.sup.7 Pa (40.10.sup.3 psi), elongation to fracture of at least about 15%, good formability and rust resistance. Alloys according to the invention can advantageously be used in devices comprising a magnetically soft body, for instance, in electro-acoustic transducers, e.g., in telephone receivers, recording heads, pole pieces, and armatures.

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Shreveport, LA, United States of America

Chester M Boredelon