Microstructures and deformation mechanisms of Cr26Mn20Fe20Co20Ni14 alloys
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)
- Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States)
Highlights: • The single-phase FCC alloy as the annealing temperature exceeding 1015 °C • The dual-phase structure as the annealing temperature lower than 1000 °C • The σ phases grow primarily at grain boundaries. • The single-phase alloy deforms via dislocations and twins. • In-situ tensile experiment reveals twinning at the crack tip. - Abstract: We investigated microstructures and tension properties of Cr{sub 26}Mn{sub 20}Fe{sub 20}Co{sub 20}Ni{sub 14} alloys that were produced by arc-melting and subsequent thermal-mechanical processing—hot-rolling → cold-rolling → annealing at different temperatures ranging from 500 °C to 1100 °C for 1 h → air cooling. Microstructure characterization shows the single-phase solid solution with face centered cubic structure as the annealing temperature exceeding 1015 °C while the dual-phase structure (Cr-rich σ phase and FCC solid solution) as the annealing temperature lower than 1000 °C. The σ phases grow primarily at grain boundaries and act as precipitation strengthening units to enhance strain hardening rate. The single-phase solid solution deforms plastically via dislocations and twins. Twin boundaries associated with deformation twinning impede dislocation motion, enhancing the strain hardening capacity. In-situ tensile experiment in transmission electron microscope further reveals that twinning occurs at the crack tip and facilitates the deflection of crack propagation towards twinning shear direction. This work implies that a strength-ductility combination can be realized by coupling precipitation strengthening and twinning-induced plasticity in multiple principle elements alloys.
- OSTI ID:
- 22804821
- Journal Information:
- Materials Characterization, Vol. 134; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
Similar Records
Experimental and Computational Investigation of High Entropy Alloys for Elevated-Temperature Applications
Bifunctional nanoprecipitates strengthen and ductilize a medium-entropy alloy