Effect of long-term 1093 K exposure to air or vacuum on the structure of several wrought superalloys
- NASA, Cleveland, OH (United States). Lewis Research Center
Long-term 1,093 K heat treatments of three commercial superalloy sheet materials were undertaken in air and vacuum. With either exposure, significant precipitation of second phases occurred in the Co-base Haynes Alloy 188 (HA 188) and the Ni-base Haynes Alloy 230 (HA 230); however, much less precipitation was found in the exposed Ni-base alloy Inconel 617 (IN 617). Although some grain growth occurred in HA 188, no changes in the grain size of either HA 230 or IN 617 were observed after 22,500 h at temperature. Oxidation during air heat treatments led to weight gain due to the formation of chromia + spinel scales and surface-connected grain boundary pits/oxides in all three superalloys. Both the weight gain and depth of intergranular attack were dependent on the square root of time, which is indicative of diffusion-controlled phenomena. Because many alloy samples had neighbors in close proximity, most vacuum heat treated specimens did not suffer significant loss of volatile elements. However, some exposed samples were subjected to unrestricted vacuum heat treatments, allowing estimates of volatilization to be made. Based on the data for HA 188, the weight loss during 1,093 K vacuum exposure was diffusion controlled once the inhibiting effects of surface films on the as-received alloys were broken down.
- OSTI ID:
- 5360882
- Journal Information:
- Journal of Materials Engineering and Performance; (United States), Journal Name: Journal of Materials Engineering and Performance; (United States) Vol. 2:5; ISSN 1059-9495; ISSN JMEPEG
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanical properties of Haynes alloy 188 after 22,500 hours of exposure to LiF-22CaF[sub 2] and vacuum at 1,093 K
Tensile properties of Haynes alloy 230 and Inconel 617 after long exposures to LiF-22CaF[sub 2] and vacuum at 1,093 K
Related Subjects
360102 -- Metals & Alloys-- Structure & Phase Studies
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOY-CO36CR22NI22W15FE3
ALLOY-NI54CR22CO13MO9
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COBALT ALLOYS
COBALT BASE ALLOYS
CONVERSION
CORROSION RESISTANT ALLOYS
DATA
ENERGY CONVERSION
EXPERIMENTAL DATA
HAYNES 188 ALLOY
HAYNES ALLOYS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INCONEL 617
INCONEL ALLOYS
INFORMATION
IRON ALLOYS
LANTHANUM ADDITIONS
LANTHANUM ALLOYS
MATERIALS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NUMERICAL DATA
OXIDATION
RARE EARTH
RARE EARTH ALLOYS
SOLAR ENERGY CONVERSION
SOLAR THERMAL CONVERSION
SPACE FLIGHT