Strengthening and fracture mechanisms of Fe–20Ni–14Cr–2Cu alumina-forming austenitic steel during creeping
Publication Name
Journal of Materials Science
Abstract
The strengthening and fracture mechanisms of Fe–20Ni–14Cr–2Cu alumina-forming austenitic (AFA) steel during creeping at 973 K/130 MPa were systematically investigated. Microstructural observations show that during creep after priorly aged at 973 K for different times, three main types of precipitates, i.e., Laves, B2-NiAl, and σ phases, are found in Fe–20Ni–14Cr–2Cu AFA steel. Laves and B2-NiAl phases dispersed in austenitic matrix contribute to the creep properties of AFA steel due to their small particle sizes, while the coarsening of hard-brittle σ phase in δ-ferrite region seems to be the main reason for creep failure. The Fe–20Ni–14Cr–2Cu AFA steel priorly aged for 1000 h possesses excellent creep property at 973 K with the minimum steady-state creep rate of 7.64 × 10–6 s−1 and the longest creep life of 329.5 h. The contribution of Laves and B2-NiAl phases to creep strength of AFA steel at 973 K/130 MPa after priorly aged for 1000 h is 261.2 MPa.
Open Access Status
This publication is not available as open access
Volume
57
Issue
43
First Page
20472
Last Page
20484
Funding Number
U1960204
Funding Sponsor
National Natural Science Foundation of China