An APFIM and TEM study of Ni{sub 4}Mo precipitation in a commercial Ni-28% Mo-1.4% Fe-0.4% Cr wt. % alloy
- Loughborough Univ. (United Kingdom). Inst. of Polymer Technology and Materials Engineering
- Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
Ni-Mo alloys containing at least 26 wt.% Mo have a negligible corrosion rate in boiling 10% hydrochloric acid and are therefore used in corrosive environments. A series of commercial Ni-Mo alloys has been developed with subtle variations in chemical composition. These alloys usually contain {approximately} 28 wt.% Mo with additions of up to 5% Fe and Cr. A significant amount of research has been performed to understand the microstructure and properties of these alloys, although most of the effort has concentrated on the Ni-Mo binary system. In some alloys with low Fe and Cr contents, a severe embrittlement problem has been observed due to the formation of the Ni{sub 4}Mo (D1{sub a}-ordered) phase within the microstructure. This research focuses on a commercial alloy with nominal composition Ni-28% Mo-1.4% Fe-0.4% Cr-0.1% Mn-0.003 wt.% C. The material supplied was a heat treatment coupon which had been attached to a large vessel during fabrication. Assessment of the chemical analysis of the alloy suggested that detrimental phases could be present or might appear during subsequent repair work. Therefore, it was important to assess the microstructural condition of the vessel, and in particular the kinetics of precipitation of Ni{sub 4}Mo.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464; AC05-76OR00033
- OSTI ID:
- 650361
- Report Number(s):
- ORNL/CP-96510; CONF-980713-; ON: DE98005021; BR: KC0201010; TRN: AHC2DT04%%275
- Resource Relation:
- Conference: Microscopy and microanalysis 1998, Atlanta, GA (United States), 12-16 Jul 1998; Other Information: PBD: Feb 1998
- Country of Publication:
- United States
- Language:
- English
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