Micromechanical behaviour of Ni-based superalloys close to the yield point: a comparative study between neutron diffraction on different polycrystalline microstructures and crystal plasticity finite element modelling

Deformation Mechanisms in Ni-Based Superalloys at Room and Elevated Temperatures Studied by In Situ Neutron Diffraction and Electron Microscopy

“…Therefore, very similar deformation mechanisms seem to be active in the two different materials, which is a result of the similar size of the γ -precipitates. In [20], it was noted that the dominant deformation mechanism in the Haynes 282 samples was shearing of the γ -precipitates, as a nearly identical mechanical behavior between the γand the γ -phase, was observed. This is in good agreement with the microstructural investigations of VDM 780 in this work.…”

“…The main differences in chemical composition in comparison with VDM 780 is a lower Cocontent (10 wt.%) and a higher Mo-and Ti-content (8.5/2.1 wt.%). The Haynes 282 samples in this comparative study [20] were solution annealed at 1010 • C for two hours, then water-quenched, and afterward age-hardened at 788 • C for eight hours and air-cooled. The Haynes samples had a similar microstructure as the VDM 780 samples after this heat treatment [20].…”

“…The Haynes 282 samples in this comparative study [20] were solution annealed at 1010 • C for two hours, then water-quenched, and afterward age-hardened at 788 • C for eight hours and air-cooled. The Haynes samples had a similar microstructure as the VDM 780 samples after this heat treatment [20]. The γ-grain size was approximately 22 µm and the diameter of the γprecipitates was about 25 nm.…”

“…This is in good agreement with the microstructural investigations of VDM 780 in this work. [20]. The tensile test with Haynes 282 was stopped at a specimen strain of about 6.5%.…”

“…Neutrons facilitate the investigation of real bulk samples, typically several cubic centimeters, because of their high penetration depth and spot size [10,11,16]. In situ ND tensile tests are a well-established method to correlate the macroscopic material behavior to the deformation behavior in the crystallographically differently oriented grains under various loading conditions or elevated temperatures [17][18][19][20][21]. The ND method is based on Bragg's law (1), where λ is the incident wavelength of the radiation, 2θ (hkl) is the diffraction angle, and d (hkl) is the lattice spacing of the (hkl) lattice plane.…”