The influence of grain boundaries on the kinetics of solid-phase reactions in a nickel-based superalloy

Valiev, Ruslan Z.; Сергеев, В. И.; Khalikov, A. M.; Shvetsova, E. V.

doi:10.1007/bf00720697

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…Meanwhile, since the adiabatic heat generated during the thermal deformation process does not have enough time to transfer due to the high strain rate of 10 s −1 , bands of flow localization are prone to occur [24]. While the deformation temperature increased, the mobility of grain boundary was enhanced, leading to the increasing rate of grain boundaries migration [25]. So, the DRX grains can easily grow up under high deformation temperatures like 1180 • C, as shown in Figures 8-10 and Figure 11f,g.…”

Section: Optical Microstructure Analysismentioning

confidence: 99%

Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

Yao

Wang

Dong

et al. 2020

Metals

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The hot deformation behavior of an advanced nickel-based Haynes282 superalloy was systematically investigated employing isothermal compression tests in the sub-solvus and super-solvus temperature with various strain rates. The influence of deformation temperature and strain rate on the microstructure was studied by transmission electron microscope. The results reveal that the interaction between work hardening and dynamic softening did not reach equilibrium under lower deformation temperature and higher strain rate. The active energy of alloy is around 537.12 kJ/mol and its hot deformation constitutive relationship equation was expressed. According to the processing map and microstructure observations, two unsafe flow instability domains should be avoided. The optimum hot processing condition for homogeneous and fine dynamic recrystallization grains are obtained. TEM micrograph observations indicated that deformation temperature and strain rate affected recrystallization by affecting the evolution of dislocation substructures within the alloy. The nucleation and growth of DRX grains can be promoted by the relatively high deformation temperature and low strain rate. The main mechanism of dynamic recrystallization nucleation preferred to discontinuous dynamic recrystallization and the typical feature of discontinuous dynamic recrystallization showed grain boundary migration nucleation. The findings improve the understanding of hot deformation behavior and dislocation substructures evolution of the superalloy, which benefits the accurate control of microstructures of nickel-based superalloys, and tailors the properties of final components used in the land-based gas turbine.

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Section: Optical Microstructure Analysismentioning

confidence: 99%

Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

Yao

Wang

Dong

et al. 2020

Metals

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High Coercive State in Submicrograined Highly Deformed Fe-Cr-Co Alloy

Stolyarov

Salimgareev

Valiev

et al. 1992

Phys. Stat. Sol. (a)

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The influence of an initial submicrograined microstructure on the decomposition kinetics, particle morphology, and high coercive state formation is studied in the hard magnetic Fe‐Cr‐Co alloy. The alloy with grain size < 1 m̈m is obtained by the method of high plastic shearing strains under high pressure. The Curie and spinodal decomposition temperatures decrease in the alloy after such treatment. The high coercive state is formed in the deformed alloy at lower temperatures of isothermal thermomagnetic treatment than in the non‐deformed one, and this state is optimal at temperatures close to those of spinodal decomposition. The dependence of coercive force on the isothermal thermomagnetic treatment temperature has extreme character with a maximum value of Hc = 40 kA/m.

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Diffusion along grain boundaries with non-equilibrium structure

Valiev

Razumovskiǐ

Сергеев

1993

Phys. Stat. Sol. (a)

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This paper is concerned with diffusion in grain boundaries with non‐equilibrium structure formed during the interaction of grain boundaries with lattice dislocations and discusses problems of the experimental analysis and evaluation of the grain boundary diffusivity taking into account grain boundary structure recovery and possible development of grain boundary migration. Experimental data are discussed on the acceleration of diffusion in grain boundaries after a non‐equilibrium structure has been formed by a specific treatment of the material: after cold pre‐straining and after a superfine grained structure has been formed. Data characterizing the grain boundary diffusivity under high‐temperature deformation are analyzed. In conclusion, some important theoretical and experimental aspects of diffusion along non‐equilibrium grain boundaries are emphasized.

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The influence of grain boundaries on the kinetics of solid-phase reactions in a nickel-based superalloy

Cited by 3 publications

References 4 publications

Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

Characterization of Hot Deformation Behavior and Dislocation Structure Evolution of an Advanced Nickel-Based Superalloy

High Coercive State in Submicrograined Highly Deformed Fe-Cr-Co Alloy

Diffusion along grain boundaries with non-equilibrium structure

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