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Accession Number:
ADA067899
Title:
MICROSTRUCTURAL STABILITY AND STRENGTH OF THE CO,CR-(CR,CO)7C3 IN-SITU COMPOSITE.
Corporate Author:
DREXEL UNIV PHILADELPHIA PA DEPT OF MATERIALS ENGINEERING
Report Date:
1979-03-01
Abstract:
The effect of elevated temperature isothermal exposure and thermal cycling on microstructural stability and compressive strength of the in-situ rod-like composite Co,CrCr,Co7C3 Vf approx. 0.3 has been examined. Microstructures were characterized by optical and electron metallography, x-ray point analysis and electron diffraction. Strength was evaluated in compression at ambient and elevated temperatures. Changes in microstructure with post-solidification treatments are shown to arise from a combination of precipitation and dissolution of Co,Cr23C6, rounding and splitting of the primary Co,Cr7C3 fibers, spheroidization of constituents and void formation at fiber-matrix interfaces. The observed strength changes are analyzed in terms of a dispersion-hardening model. Failure in compression below the ductile to brittle transition temperature of the reinforcement occurs by shear in the matrix accompanied by transverse cleavage of the fibers. Above the ductile-to-brittle transition temperature of the reinforcing phase both matrix and carbide exhibit plastic flow. Author
Descriptive Note:
Final rept.,
Pages:
0044
Contract Number:
N00014-76-C-0205
File Size:
15.33MB
