Irradiation-induced precipitation in direct-aged alloy 625
- Westinghouse Electric Corp., West Mifflin, PA (United States)
Direct-aged alloy 625 (DA-A625) is a precipitation-hardened nickel-base superalloy with good mechanical properties and excellent corrosion resistance. Its superior stress corrosion cracking (SCC) performance makes it a candidate material for applications in light water reactors where resistance to irradiation assisted SCC (IASCC) is important. This alloy derives its strength from the intragranular precipitation of fine DO{sub 22} - ordered {gamma}{double_prime} precipitates. These precipitates have a disc-like morphology and are crystallographically related to the {gamma} matrix such that the [001] axis of the precipitates are oriented parallel to <100> directions in the matrix. This alloy is generally solution-annealed then aged within the temperature range directions in the matrix. This alloy is generally solution-annealed then aged within the temperature range {approximately}600 to 750{degrees}C. In direct-aging, the alloy is immediately aged at {approximately}660{degrees}C for 80 h following hot-working. In addition to the {gamma}{double_prime} precipitates, intergranular M{sub 23}C{sub 6}, M{sub 7}C{sub 3}, M{sub 6}C, or MC carbides can form in this material. To evaluate the effect of neutron irradiation on the microstructure and IASCC behavior of Alloy 625 specimens in the direct-aged condition were neutron-irradiated at 370{degrees}C and 265{degrees}C to a fluence of {approximately}10{sup 20} neutrons/cm{sup 2} (E > 1 MeV). Conventional thin-foil specimens were prepared using 20% HClO{sub 4} - 80% CH{sub 3}OH at {approximately}-40{degrees}C, and subsequently examined in Philips CM12 and CM30 analytical electron microscopes.
- OSTI ID:
- 468955
- Report Number(s):
- CONF-960877-; TRN: 97:001308-0213
- Resource Relation:
- Conference: Microscopy and microanalysis 1996, Minneapolis, MN (United States), 11-15 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Microscopy and microanalysis 1996; Bailey, G.W.; Corbett, J.M.; Dimlich, R.V.W.; Michael, J.R.; Zaluzec, N.J. [eds.]; PB: 1107 p.
- Country of Publication:
- United States
- Language:
- English
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