Microstructure evolution and constitutive model for a Ni-Mo-Cr base alloy in double-stages hot compression with step-strain rates

He, Dao‐Guang; Yan, Xin-Tao; Lin, Y.C.; Zhang, Song; Chen, Zi‐Jiang

doi:10.1016/j.matchar.2022.112385

Cited by 17 publications

(7 citation statements)

References 53 publications

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“…The above models are the quadratic models for single-variable fitting, collectively designated as B. As mentioned for equation (6), a 0 , b 0 , and c 0 depend on y and a 1 , b 1 , and c 1 depend on x. Activation energy Q d is calculated by taking the ratio of the average values of slopes in equation (2). It may be emphasized that apparent activation energy for all constitutive models in the present investigation is calculated using equation (2).…”

Section: ( ) = + +mentioning

confidence: 99%

“…Optimized sets of temperature and strain rate result in desirable mechanical properties. Owing to its importance for controlling final mechanical properties, hot deformation of alloys is an extensively studied field of materials processing [2][3][4][5][6][7][8]. Appropriate knowledge of material flow and microstructural behavior during hot working is crucial for selecting suitable temperatures and strain rates.…”

Section: Introductionmentioning

confidence: 99%

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Nonlinear multivariate constitutive equations for modeling hot deformation behavior

Ahmedabadi

2023

Mater. Res. Express

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Nonlinear constitutive equations are proposed to model variations in flow stress as a function of strain rate and temperature during hot deformation. Modified constitutive are applied to seventy data sets about hot deformation of alloys. Two modifications to conventional constitutive models are introduced, viz. (1) nonlinear and (2) multivariate models with the fitting of flow stress simultaneously with two variables. The predictive accuracy of constitutive equations was evaluated using three statistical parameters and compared with aconventional Arrhenius-like model. It is shown that nonlinear constitutive equations have improved predictive accuracy for variations in flow stress during hot deformation. The advantages of multivariate models include less computation and material parameters that are constants independent of temperature or strain rate. In another type of multivariate model, flow stress is expressed as linear and nonlinear polynomial functions of the Zener-Holloman parameter. This approach gives a single value of the activation energy of hot deformation.The results have indicated that a generalized second-order multivariate constitutive equation can be used to better predict flow stress, as a function strain rate and temperature, during hot deformation.

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Section: ( ) = + +mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nonlinear multivariate constitutive equations for modeling hot deformation behavior

Ahmedabadi

2023

Mater. Res. Express

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“…The predominant cause is that the shorter deforming time for the dislocations' climbing/interaction and the propagation of grain boundaries can be ensured at higher . ε [29,39].…”

Section: Microstructure Evolution Mechanismsmentioning

confidence: 99%

“…For instance, the evolution features of flow behaviors with the Zener-Hollomon (Z) parameters were explored, and various phenomenological equations were constructed for depicting hot deforming features in aluminum alloys [32][33][34]. Meanwhile, numerous physically based (PB) equations were constructed to predict the hot flow stress and microstructures for aluminum alloys [35][36][37][38], Ni-based alloys [39] and ultrahigh-strength steels [40,41]. In addition, various artificial neural network (ANN) models [42][43][44] containing BP models [45][46][47] and long short-term memory (LSTM) models [48,49] have been used to predict hot flow behaviors in aluminum alloys.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Compression Behaviors and Constitutive Models of a 7046-Aluminum Alloy

He,

Xie,

Lin

et al. 2023

Materials

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High-temperature forming behaviors of a 7046-aluminum alloy were investigated by hot compression experiments. The microstructural evolution features with the changes in deformation parameters were dissected. Results indicated the formation of massive dislocation clusters/cells and subgrains through the intense DRV mechanism at low compression temperature. With an increase in deformation temperature, the annihilation of dislocations and the coarsening of subgrains/DRX grains became prominent, due to the collaborative effects of the DRV and DRX mechanisms. However, the growth of subgrains and DRX grains displayed the weakening trend at high strain rates. Moreover, two constitutive models involving a physically based (PB) model and a gate recurrent unit (GRU) model were proposed for predicting the hot compression features. By validation analysis, the predicted values of true stress perfectly fit with the experimental data, indicating that both the proposed PB model and the GRU model can accurately predict the hot compression behaviors of 7046-aluminum alloys.

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“…Taking into account the combined impact of dynamic recovery (DRV) and dimples, Wen et al [ 40 ] modeled the high-temperature tensile characteristics of an ultra-high strength steel utilizing a PB equation. Similarly, multiple PB equations were established or modified for reconstituting the hot deformation features of alloys, i.e., Hastelloy C276 alloy [ 41 ], steel [ 42 ] and Mg-9%Al-1%Zn [ 43 ]. Additionally, various artificial neural network algorithms [ 44 , 45 ], containing support vector regression (SVR) [ 46 ], long short-term memory (LSTM) [ 47 ] and back propagation (BP) combined with the particle swarm optimization (PSO) algorithm [ 48 ], were employed to model the hot deformation characteristics of alloys.…”

Section: Introductionmentioning

confidence: 99%

Hot Deformation Behavior of Hastelloy C276 Alloy: Microstructural Variation and Constitutive Models

He,

Chen,

Lin

et al. 2023

Materials

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Isothermal deformation experiments of the Hastelloy C276 alloy were executed using the Gleeble-3500 hot simulator at a temperature range of 1000–1150 °C and a strain rate range of 0.01–10 s−1. Microstructural evolution mechanisms were analyzed via transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). Results reveal that the influences of hot compression parameters on the microstructure variation features and flow behaviors of the Hastelloy C276 alloy were significant. The intense strain hardening (SH) effects caused by the accumulation of substructures were promoted when the strain rates were increased, and true stresses exhibited a notable increasing tendency. However, the apparent DRV effects caused by the annihilation of substructures and the increasingly dynamic recrystallization (DRX) behaviors occurred at high compressed temperature, inducing the reduction in true stresses. In addition, a physical-based (PB) constitutive model and a long short-term memory (LSTM) model optimized using the particle swarm optimization (PSO) algorithm were established to predict the flow behavior of Hastelloy C276 alloy. The smaller average absolute relative error and greater relation coefficient suggest that the LSTM model possesses a higher forecasting accuracy than the PB model.

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Microstructure evolution and constitutive model for a Ni-Mo-Cr base alloy in double-stages hot compression with step-strain rates

Cited by 17 publications

References 53 publications

Nonlinear multivariate constitutive equations for modeling hot deformation behavior

Nonlinear multivariate constitutive equations for modeling hot deformation behavior

High-Temperature Compression Behaviors and Constitutive Models of a 7046-Aluminum Alloy

Hot Deformation Behavior of Hastelloy C276 Alloy: Microstructural Variation and Constitutive Models

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