Understanding the composition-dependent stability of η phase for future Ni-Co-based superalloys

Yu, Xin; Yu, Zichao; Zhang, Lina; Yu, Hongying; Zhao, Lei; Zhang, Wenyan; Ruan, Jun; Wang, Zi; Cui, Huanxian; Bi, Zhongnan; Jiang, Liang; Zhu, Lilong

doi:10.1016/j.scriptamat.2022.114886

Cited by 11 publications

(1 citation statement)

References 28 publications

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“…Therefore, it is considered to be a promising candidate material for the hot-end components in aircraft engines. However, problems are also reported for these materials, such as the structural instability due to η phase transformation at high temperature, and the cracking susceptibility under some deformation conditions [8].…”

Section: Introductionmentioning

confidence: 99%

Deformation behavior of a new Ni-Co base superalloy GH4251 during hot compression

Wang

Qin³

et al. 2023

Mater. Res. Express

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The deformation behavior of a new Ni-Co base superalloy GH4251 under hot compression tests within the deformation strain window of 0.36 to 1.2 was investigated in the temperature range of 1050~1170 °C and strain rate range of 0.001~1 s−1. Based on the analysis of true stress-strain curves, constitutive equations were established to describe the rheological behavior during hot compression. Microstructure evolution was investigated by transmission electron microscope (TEM), scanning electron microscope (SEM) and optical metallography (OM). The results show that flow behavior of GH4251 alloy is combinedly determined by the effect of work hardening and dynamic recrystallization (DRX). The deformation activation energies at strain of 0.36 to 1.2 are calculated to be 311~536 kJ/mol in the super-solvus temperature region, and 796~1064 kJ/mol in the sub-solvus temperature region. The recrystallization nucleation mechanism of GH4251 alloy is strain induced grain boundary migration (SIBGM). The occurrence and expansion of recrystallization are strongly promoted by high deformation temperatures and high strain rates, while the DRX grain size increases with elevated deformation temperature. When the deformation temperature is below 1090℃, the recrystallized grain can be extremely small (<17µm), which is rather independent on strain and strain rate. However, above 1110 ℃ the grain size at strain rate of 0.001s-1 is significantly larger than that of higher strain rates. The difference can be ascribed to the presence of γ’ phase, with which the development of dynamic recrystallization is postponed, while the growth of recrystallized grains is inhibited as well.

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Section: Introductionmentioning

confidence: 99%