Evading strength-ductility trade-off of GH605 alloy using magnetic field-assisted undercooling treatment
(1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. Center of Advanced Lubrication and Seal Materials, Northwestern Polytechnical University, Xi’an, 710072, China;
3. Collaborative Innovation Center of NPU, Shanghai 201108, China;
4. Institute of Superconducting Materials and Applied Technology, Northwestern Polytechnical University, Xi’an 710072, China;
5. Shaanxi Key Laboratory of Electrical Materials and Infiltration Technology, Xi’an University of Technology, Xi’an 710048, China)
2. Center of Advanced Lubrication and Seal Materials, Northwestern Polytechnical University, Xi’an, 710072, China;
3. Collaborative Innovation Center of NPU, Shanghai 201108, China;
4. Institute of Superconducting Materials and Applied Technology, Northwestern Polytechnical University, Xi’an 710072, China;
5. Shaanxi Key Laboratory of Electrical Materials and Infiltration Technology, Xi’an University of Technology, Xi’an 710048, China)
Abstract: Undercooling solidification under a magnetic field (UMF) is an effective way to tailor the microstructure and properties of Co-based alloys. In this study, by attributing to the UMF treatment, the strength-ductility trade-off dilemma in GH605 superalloy is successfully overcome. The UMF treatment can effectively refine the grains and increase the solid solubility, leading to the high yield strength. The main deformation mechanism in the as-forged alloy is dislocation slipping. By contrast, multiple deformation mechanisms, including stacking faults, twining, dislocation slipping, and their strong interactions are activated in the UMF-treated sample during compression deformation, which enhances the strength and ductility simultaneously. In addition, the precipitation of hard Laves phases along the grain boundaries can be obtained after UMF treatment, hindering crack propagation during compression deformation.
Key words: undercooling treatment; magnetic field; GH605 alloy; strengthening mechanisms