Short fatigue crack growth mechanism in Ni-Co based superalloy at elevated temperatures and in oxidative atmospheres

Nishikawa, Hideaki; Habib, Kishan; Furuya, Yoshiyuki; Hara, Toru; Osada, Toshio; Kawagishi, Kyoko

doi:10.1016/j.msea.2023.145655

Cited by 4 publications

(1 citation statement)

References 39 publications

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“…The National Institute for Materials Science of Japan successfully developed the TMW series Ni-Co-based superalloys first by reducing SFE [8]. Compared with the stronger cast-forged U720Li superalloy, the temperature-bearing capacity of this Ni-Co-based superalloy can be increased by 30 • C. The mechanical properties and structural stability of Ni-Co-based superalloys are better than those of the U720Li superalloy, which is expected to become a key material for hot-end components [9][10][11][12]. With the unstoppable trend of product miniaturization in many fields such as aerospace, the nuclear industry, weapons equipment, and energy, precise plastic forming technology of Ni-Co-based superalloy micro components is a key task that needs to be solved urgently.…”

Section: Introductionmentioning

confidence: 99%

Effects of Ultra-Low Temperatures on the Mechanical Properties and Microstructure Evolution of a Ni-Co-Based Superalloy Thin Sheet during Micro-Tensile Deformation

Zhu,

Wang,

Sun

et al. 2023

Materials

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With the development of product miniaturization in aerospace, the nuclear industry, and other fields, Ni-Co-based superalloys with excellent overall properties have become key materials for micro components in these fields. In the microforming field, size effects significantly impact the mechanical properties and plastic deformation behavior of materials. In this paper, micro-tensile experiments at room temperature and an ultra-low temperature were carried out to study the effects of initial microstructure and deformation temperature on the deformation behavior of Ni-Co-based superalloy thin sheets. The results show that as the ratio of specimen thickness to grain size (t/d) decreased from 8.6 to 2.4, the tensile strength σb decreased from 1221 MPa to 1090 MPa, the yield strength σs decreased from 793 MPa to 622 MPa, and the elongation decreased from 0.26 to 0.21 at room temperature. When t/d decreased from 8.6 to 2.4, σb decreased from 1458 MPa to 1132 MPa, σs decreased from 917 MPa to 730 MPa, and the elongation decreased from 0.31 to 0.28 at ultra-low temperatures. When t/d decreased from 8.6 to 2.4, the surface roughness of the specimen increased from 0.769 to 0.890 at room temperature and increased from 0.648 to 0.809 at ultra-low temperatures. During the microplastic deformation process of Ni-Co-based superalloy thin sheets, the coupled effects of surface roughening caused by free surface grains and hindered dislocation movement induced by grain boundary resulted in strain localization, which caused fracture failure of Ni-Co-based superalloy thin sheets.

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