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Showing papers on "Inconel published in 1974"


Journal ArticleDOI
TL;DR: The major phase present in the alloy after exposure to all temperatures from 1200 to 2000°F (649 to 1093°C) was found to be M23C6. The phase precipitated as discrete particles and remained stable at au temperatures as mentioned in this paper.
Abstract: INCONEL alloy 617 (54 Ni, 22 Cr, 12.5 Co, 9 Mo, 1 Al, 0.07 C) is a solid-solution alloy with good corrosion resistance and an exceptional combination of high-temperature strength and oxidation resistance. A laboratory study was performed to determine the effects of long-time (215 to over 10,000 h) exposure to temperatures up to 2000°F (1093°C) on the microstructure and phase stability of the alloy. To investigate the strengthening response exhibited by the alloy during high-temperature exposure, microstructures were correlated with mechanical properties. The major phase present in the alloy after exposure to all temperatures from 1200 to 2000°F (649 to 1093°C) was found to be M23C6. The phase precipitated as discrete particles and remained stable at au temperatures. No MC or M6C carbides were found. A small amount of gamma prime was found in samples exposed at 1200°F (649°C) and 1400°F (760°C). A PHACOMP analysis indicated 0.63 pct gamma prime could form. No topological close-packed phases such as sigma, mu, and chi were found. Strengthening of the alloy during exposure to temperature was found to result primarily from the precipitation of M23C6. The phase provides effective strengthening because it precipitates in discrete particles and remains stable at temperatures to 2000°F (1093°C). The amount of gamma prime formed is not sufficient to cause appreciable hardening, but it does provide some strengthening at 1200 to 1400°F (649 to 760°C).

186 citations


Journal ArticleDOI
TL;DR: The creep-fracture behavior of Inconel alloy X-750 at 700°C has been studied using four grain sizes ranging from 9 to 200 μm over a range of stress from 207 to 414 N/mm2 as discussed by the authors.
Abstract: The creep-fracture behaviour of Inconel alloy X-750 at 700° C has been studied using four grain sizes ranging from 9 to 200 μm over a range of stress from 207 to 414 N/mm2. Cavity nucleation was continuous through the tests, starting during primary creep. Interlinkage of cavities to form cracks of a grain-boundary facet in length was completed towards the end of the secondary stage of creep and catastrophic failure resulted when these cracks interlinked to form a crack of critical size. From the angular distribution of cavities, it was deduced that grain-boundary sliding played a dominant role during the earlier stages of the growth of cavities, whereas vacancy condensation and/or mechanical tearing were the dominant growth processes during the later stages of the growth of cavities. Ductility increased significantly as the grain size was decreased. This can be related to the extended tertiary creep stage observed in the small grain sizes as a result of the presence of a larger number of triple ju...

32 citations


01 Feb 1974
TL;DR: In this paper, the electron beam evaporation of various metals and alloys, including Ti-6 Al--4 V, Inconel 800, zirconium, and stainless steel, is discussed.
Abstract: The electron beam evaporation of various metals and alloys, including Ti- -6 Al--4 V, Inconel 800, zirconium, and stainless steel is discussed. The condensation of such evaporants to a freestanding foil is examined with regard to alloy composition control and foil metallurgy. Operating experience is also covered with consideration of source power efficiencies, deposition rates, and process control of general foil characteristics. (auth)

5 citations


01 May 1974
TL;DR: Inconel 718 superalloy was used in this paper to determine the tensile strength properties and the crack-growth behavior in electron-beam, plasma-arc, and gas tungsten are welds for plates 1.90 cm (0.75 in) thick.
Abstract: Results of mechanical-properties and axial-load fatigue and fracture tests performed on thick welded plates of Inconel 718 superalloy are presented. The test objectives were to determine the tensile strength properties and the crack-growth behavior in electron-beam, plasma-arc, and gas tungsten are welds for plates 1.90 cm (0.75 in) thick. Base-metal specimens were also tested to determine the flaw-growth behavior. The tests were performed in room-temperature-air and liquid nitrogen environments. The experimental crack-growth-rate data are correlated with theoretical crack-growth-rate predictions for semielliptical surface flaws.

5 citations


01 Jan 1974
TL;DR: The embrittlement of Inconel 718 by exposure to 34.5 MN/sq m hydrogen at ambient temperature was found to be a function of both forming operation and heat treatment as discussed by the authors.
Abstract: The embrittlement of Inconel 718 by exposure to 34.5 MN/sq m hydrogen at ambient temperature was found to be a function of both forming operation and heat treatment. The embrittlement, as measured by reduction of notch strength in hydrogen as compared to helium, was decreased by a fine-grain size and was most severe for coarse-grained structures containing a continuous or nearly continuous precipitate tentatively identified as Ni3Cb. Tests performed on unnotched specimens showed that the strain at which surface cracks initiate in 34.5 MN/sq m hydrogen was approximately 3% and was independent of prior forming operation or heat treatment.

4 citations