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Effect of reduced cobalt contents on hot isostatically pressed powder metallurgy U-700 alloysThe effect of reducing the cobalt content of prealloyed powders of UDIMET 700 (U-700) alloys to 12.7, 8.6, 4.3, and 0% was examined. The powders were hot isostatically pressed into billets, which were given heat treatments appropriate for turbine disks, namely partial solutioning at temperatures below the gamma prime solvus and four step aging treatments. Chemical analyses, metallographic examinations, and X-ray diffraction measurements were performed on the materials. Minor effects on gamma prime content and on room temperature and 650 C tensile properties were observed. Creep rupture lives at 650 C reached a maximum at the 8.4% concentration, while at 760 C a maximum in life was reached at the 4.3% cobalt level. Minimum creep rates increased with decreasing cobalt content at both test temperatures. Extended exposures at 760 and 815 C resulted in decreased tensile strengths and rupture lives for all alloys. Evidence of sigma phase formation was also found.
Document ID
Document Type
Conference Paper
Harf, F. H.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 11, 2013
Publication Date
October 1, 1982
Publication Information
Publication: COSAM (Conserv. Of Strategic Aerospace Mater.) Program Overview
Subject Category
Metallic Materials
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.

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