Precipitation of an intermetallic phase with Pt{sub 2}Mo-type structure in alloy 625

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0194-6· OSTI ID:316068

Sundararaman, M; Kumar, L; Prasad, G E; Mukhopadhyay, P; Banerjee, S ^[1]

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1. Bhabha Atomic Research Centre, Mumbai (India). Materials Science Div.

The microstructure of Alloy 625, which has undergone prolonged ({approximately}70,000 hours) service at temperatures close to but less than 600 C, has been characterized by transmission electron microscopy. The precipitation of an intermetallic phase Ni{sub 2}(Cr, Mo) with Pt{sub 2}Mo-type structure has been observed in addition to that of the {gamma}{double_prime} phase. Six variants of Ni{sub 2} (Cr, Mo) precipitates have been found to occur in the austenite grains. These particles exhibit a snowflake-like morphology and are uniformly distributed in the matrix. They have been found to dissolve when the alloy is subjected to short heat treatments at 700 C. The occurrence of the Ni{sub 2}(Cr, Mo) phase has been discussed by taking the alloy chemistry into consideration. Apart from the intermetallic phases, the precipitation of a M{sub 6}C-type carbide phase within the matrix and the formation of near continuous films, comprising discrete M{sub 6}C/M{sub 23}C{sub 6} carbide particles, at the austenite grain boundaries have been noticed in the alloy after prolonged service.

• Sponsoring Organization: USDOE
• OSTI ID: 316068
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 1 Vol. 30; ISSN MMTAEB; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
AUSTENITE
CARBIDES
INCONEL 625
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
PRECIPITATION