Microstructures and deformation mechanisms of Cr26Mn20Fe20Co20Ni14 alloys

作者：Ming, Kaisheng; Bi, Xiaofang^*; Wang, Jian^*

来源：Materials Characterization, 2017, 134: 194-201.

DOI：10.1016/j.matchar.2017.10.022

• Metallic alloys
• Twinning
• Precipitation
• Strength
• Ductility

We investigated microstructures and tension properties of Cr26Mn20Fe20Co20Ni14 alloys that were produced by arc-melting and subsequent thermal-mechanical processing hot-rolling -> cold-rolling -> annealing at different temperatures ranging from 500 degrees C to 1100 degrees 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 degrees C while the dual-phase structure (Cr-rich sigma phase and FCC solid solution) as the annealing temperature lower than 1000 degrees C. The sigma 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.

• 出版日期2017-12
• 单位北京航空航天大学