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Precipitation strengthened high strength, high conductivity Cu-Cr-Nb alloys produced by chill block melt spinningA series of Cu-based alloys containing 2 to 10 a/o Cr and 1 to 5 a/o Nb were produced by chill block melt spinning (CBMS). The melt spun ribbons were consolidated and hot rolled to sheet to produce a supersaturated Cu-Cr-Nb solid solution from which the high melting point intermetallic compound Cr2Nb could be precipitated to strengthen the Cu matrix. The results show that the materials possess electrical conductivities in excess of 90 percent that of pure Cu at 200 C and above. The strengths of the Cu-Cr-Nb alloys were much greater than Cu, Cu-0.6 Cr, NARloy-A, and NARloy-Z in the as-melt spun condition. The strengths of the consolidated materials were less than Cu-Cr and Cu-Cr-Zr below 500 C and 600 C respectively, but were significantly better above these temperatures. The strengths of the consolidated materials were greater than NARloy-Z, at all temperatures. The GLIDCOP possessed similar strength levels up to 750 C when the strength of the Cu-Cr-Nb alloys begins to degrade. The long term stability of the Cu-Cr-Nb alloys was measured by the microhardness of aged samples and the growth of precipitates. The microhardness measurements indicate that the alloys overage rapidly, but do not suffer much loss in strength between 10 and 100 hours which confirms the results of the electrical resistivity measurements taken during the aging of the alloys at 500 C. The loss in strength from peak strength levels is significant, but the strength remains exceptionally good. Transmission electron microscopy (TEM) of the as-melt spun samples revealed that Cr2Nb precipitates formed in the liquid Cu during the chill block melt spinning, indicating a very strong driving force for the formation of the precipitates. The TEM of the aged and consolidated materials indicates that the precipitates coarsen considerably, but remain in the submicron range.
Document ID
19900002537
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Ellis, David L. (Case Western Reserve Univ. Cleveland, OH, United States)
Michal, Gary M. (Case Western Reserve Univ. Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
September 1, 1989
Subject Category
Metallic Materials
Report/Patent Number
NAS 1.26:185144
NASA-CR-185144
Accession Number
90N11853
Funding Number(s)
CONTRACT_GRANT: NGT-50087
PROJECT: RTOP 553-13-00
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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