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Title: High strength bulk Fe-Co alloys produced by powder metallurgy

Abstract

Fe-Co alloys are extensively used in lamination form, but there are certain power generation applications that require Fe-Co rotors in bulk form. Experiencing only a dc magnetic field, these rotors can be as large as 0.5 m in diameter, depending on the size of the generator. The forging of such large pieces of Fe-Co has proven to be difficult. The present study investigates powder metallurgy processing of a gas atomized FeCoNbV alloy through hot isostatic pressing (HIP) for manufacturing large size rotors with improved mechanical strength. Gas atomized FeCoNbV alloy powders with and without ball milling were hot isostatic pressed at temperatures between 675 and 850 deg. C at a fixed pressure of 193 MPa for up to 6 h. Ball milling prior to HIP improved the yield strength. A further improvement in yield strength and in ductility was obtained after a disordering heat treatment at 730 deg. C followed by a rapid quench to room temperature. The optimum HIP and annealing conditions resulted in samples with yield strengths of 870 MPa. The compacts exhibited average coercivity values of 6.4 Oe and maximum permeability values of 1100.

Authors:
;  [1]; ;  [2]
  1. UES Inc., 4401 Dayton-Xenia Rd., Dayton Ohio 45432 (United States)
  2. AFRL, Wright-Patterson AFB, Ohio 45433 (United States)
Publication Date:
OSTI Identifier:
21137326
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 103; Journal Issue: 7; Conference: 52. annual conference on magnetism and magnetic materials, Tampa, FL (United States), 5-9 Nov 2007; Other Information: DOI: 10.1063/1.2838466; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; COBALT ALLOYS; COERCIVE FORCE; DUCTILITY; FERROMAGNETIC MATERIALS; HOT PRESSING; IRON ALLOYS; MAGNETIC FIELDS; MAGNETIC SUSCEPTIBILITY; MILLING; NIOBIUM ALLOYS; PERMEABILITY; POWDER METALLURGY; PRESSURE DEPENDENCE; PRESSURE RANGE MEGA PA 100-1000; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; TIME DEPENDENCE; YIELD STRENGTH

Citation Formats

Turgut, Zafer, Meiqing, Huang, AFRL, Wright-Patterson AFB, Ohio 45433, Horwath, John C, and Fingers, Richard T. High strength bulk Fe-Co alloys produced by powder metallurgy. United States: N. p., 2008. Web. doi:10.1063/1.2838466.
Turgut, Zafer, Meiqing, Huang, AFRL, Wright-Patterson AFB, Ohio 45433, Horwath, John C, & Fingers, Richard T. High strength bulk Fe-Co alloys produced by powder metallurgy. United States. doi:10.1063/1.2838466.
Turgut, Zafer, Meiqing, Huang, AFRL, Wright-Patterson AFB, Ohio 45433, Horwath, John C, and Fingers, Richard T. Tue . "High strength bulk Fe-Co alloys produced by powder metallurgy". United States. doi:10.1063/1.2838466.
@article{osti_21137326,
title = {High strength bulk Fe-Co alloys produced by powder metallurgy},
author = {Turgut, Zafer and Meiqing, Huang and AFRL, Wright-Patterson AFB, Ohio 45433 and Horwath, John C and Fingers, Richard T},
abstractNote = {Fe-Co alloys are extensively used in lamination form, but there are certain power generation applications that require Fe-Co rotors in bulk form. Experiencing only a dc magnetic field, these rotors can be as large as 0.5 m in diameter, depending on the size of the generator. The forging of such large pieces of Fe-Co has proven to be difficult. The present study investigates powder metallurgy processing of a gas atomized FeCoNbV alloy through hot isostatic pressing (HIP) for manufacturing large size rotors with improved mechanical strength. Gas atomized FeCoNbV alloy powders with and without ball milling were hot isostatic pressed at temperatures between 675 and 850 deg. C at a fixed pressure of 193 MPa for up to 6 h. Ball milling prior to HIP improved the yield strength. A further improvement in yield strength and in ductility was obtained after a disordering heat treatment at 730 deg. C followed by a rapid quench to room temperature. The optimum HIP and annealing conditions resulted in samples with yield strengths of 870 MPa. The compacts exhibited average coercivity values of 6.4 Oe and maximum permeability values of 1100.},
doi = {10.1063/1.2838466},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 7,
volume = 103,
place = {United States},
year = {2008},
month = {4}
}