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U.S. Department of Energy
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ELECTRON METALLOGRAPHIC STUDIES OF NICKEL-BASE HEAT-RESISTANT ALLOYS

Technical Report ·
OSTI ID:4278802
Methods are described which have proven satisfactory for polishing and etching nickel-base alloys for electron metallographic examinations. Extraction replica techniques for isolating gamma and carbide partlcles from the alloys for study by selected-area electron diffraction are also given. Electron microscopic studies were made of the changes in microstructures of the commercial alloys, Inconel-X, Waspaloy, M-252, and Udimet-500, during aging at 1400 and 1600 deg F. Hardness variations are correlated with the precipitation of the gamma phase, and the possible mechanisms contributing to the observed variations are discussed. Electron diffraction studies showed that the gamma phase has an ordered structure, and precipitates with a preferred orientation in the matrix. Lineal and spectrographic analyses indicate that the composition of the phase is more complex than is indicated by the usual formulas of Ni/sub 3/Al and Ni/sub 3/ (Al,Ti). Microstructural studies were made of an experimental alloy of high Ti and Al content, and of a cast nickel-base alloy. Investigations were made to determine the nature of a banded structure which is associated with low rupture strength, and to study the influence of small additions of boron and zirconium on the precipitation of the gamma phase. (auth)
Research Organization:
Michigan. Univ., Ann Arbor. Research Inst.
NSA Number:
NSA-13-008999
OSTI ID:
4278802
Report Number(s):
WADC-TR-58-406; AD-155767
Country of Publication:
United States
Language:
English