Powder Metallurgy Processing of High-Strength FeCo Alloys (Preprint)
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 meter 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 (PM) 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 HIP'ed at temperatures between 675 deg C and 800 deg C at a fixed pressure of 193 MPa for up to 6 hours. 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2008
- Accession Number
- ADA489020
Entities
People
- John C. Horwath
- Richard T. Fingers
- Zafer Turgut
Organizations
- Air Force Research Laboratory