Abstract
Austenitization with lower temperature and intercritical annealing were introduced in the treatment of a maraging steel with a composition of Fe–12.94Ni–1.61Al–1.01Mo–0.23Nb (wt.%). Scanning electron microscopy was employed to study the microstructure after austenitization at 950 °C and intercritical annealing, followed by aging at 485 and 600 °C. X-ray diffraction (XRD) analysis was applied to evaluate the formation of retained or reverted austenite. Thermodynamic calculation was employed to calculate equilibrium phase mole fractions. Hardness and Charpy impact toughness of the steel were measured. Intercritical annealing treatments did not result in significant increase of hardness either before or after aging. The Charpy impact toughness of the alloy in aged condition was enhanced after austenitization at 950 °C. No austenite was observed in XRD. However, suspected reverted austenite was found after austenitization at 950 °C followed by aging at 600 °C for 4 h. Relationships among heat treatment, microstructure and mechanical properties are discussed.
Original language | English |
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Pages (from-to) | 129-135 |
Number of pages | 7 |
Journal | Materials Science and Engineering: A |
Volume | 536 |
Early online date | 27 Dec 2011 |
DOIs | |
Publication status | Published - 28 Feb 2012 |
Keywords
- Mechanical properties
- Steel
- Aging
- Fracture
- Heat treatment
- Phase transformations
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanical Engineering
- Mechanics of Materials