Microstructural changes in alloy 625 during high temperature creep

• Published in: Materials characterization Vol. 59; no. 5; pp. 508 - 513
• Main Authors: Mathew, M.D., Parameswaran, P., Bhanu Sankara Rao, K.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2008; Elsevier Science
• Subjects: Alloy 625; Applied sciences; Creep; Cross-disciplinary physics: materials science; rheology; Delta-phase; Exact sciences and technology; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Solidification; γ-phase; γ-phase; Creep; Microstructure; Alloy 625; Delta-phase; Nickel base alloys; Temperature; Mechanical properties; High temperature; Alloy 625,Creep,Microstructure,Delta-phase,γ-phase
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2007.03.007

Microstructural changes in the nickel-base alloy 625 during creep deformation have been investigated in the temperature range of 923 to 1148 K for durations from 30 to 31,800 h. Intermetallic phases such as γ″-phase and δ-phase have been found to precipitate extensively within the austenitic matrix under most of the test conditions. The γ″-phase was observed at 973 K and δ-phase was observed at all temperatures above 973 K. The morphology of the needle-shaped δ-phase was influenced by time and temperature of exposure and stress. An almost continuous decoration of M 23C 6 type carbides was observed on the grain boundaries.