Modeling of the Hot Flow Behaviors for Ti-6Al-4V-0.1Ru Alloy by GA-BPNN Model and Its Application

2018 ◽  
Vol 37 (6) ◽  
pp. 551-562 ◽  
Author(s):  
Yu-ting Zhou ◽  
Yu-feng Xia ◽  
Lai Jiang ◽  
Shuai Long ◽  
Dong Yang
Keyword(s):  
Strain Rate ◽  
Back Propagation ◽  
Interaction Space ◽  
Processing Parameters ◽  
Back Propagation Neural Network ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Strain And Strain Rate ◽  
Deformation Behaviors ◽  
Bpnn Model

AbstractA series of compression tests were performed on Ti-6Al-4V-0.1Ru titanium alloy in nine temperatures between 750 and 1150 °C and a strain rate range of 0.01 to 10s−1. The hot deformation behaviors of Ti-6Al-4V-0.1Ru showed highly non-linear intrinsic relationships with temperature, strain and strain rate. The flow curves exhibited different softening mechanisms, dynamic recrystallization (DRX) and dynamic recovery (DRV). In this study, the rheological behaviors of Ti-6Al-4V-0.1Ru were modeled using a special hybrid prediction model, where genetic algorithm (GA) was implemented to do a back-propagation neural network (BPNN) weights optimization, namely GA-BPNN. Subsequently, the predicted results were compared with experimental values and GA-BPNN model showed the ability to predict the flow behaviors of Ti-6Al-4V-0.1Ru with superior accuracy. Then a 3-D continuous interaction space was constructed to visually reveal the successive relationships among processing parameters. Finally, the predicted data were applied to process simulation and accuracy results were achieved.

scholarly journals Study on the Evolution of Damage Degradation at Different Temperatures and Strain Rates for Ti-6Al-4V Alloy

2019 ◽  
Vol 38 (2019) ◽  
pp. 332-341
Author(s):  
Lin Gao ◽  
Jiang Zhao ◽  
Guo-zheng Quan ◽  
Wei Xiong ◽  
Chao An
Keyword(s):  
Strain Rate ◽  
Ductile Fracture ◽  
Element Model ◽  
Processing Parameters ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Different Temperatures ◽  
Strain Stress ◽  
Effects Of Temperature ◽  
The Finite Element Model

AbstractIt is a significant issue to deeply understand the nature relationships between damage degradation and deforming parameters, and then identify the changes of initial ductile fracture time with processing parameters and further adjusting the forming processes for obtaining the fracture-free components. For Ti-6Al-4V alloy, the strain-stress data in the temperature range of 1023–1323 K and strain rate range of 0.01–10 s−1 were obtained by compression tests. The finite element model with stress-strain data was constructed to simulate the ductile damage cumulating processes under different conditions and obtained the maximum damage values. Subsequently, the ductile fracture criterion (DFC) of Ti-6Al-4V alloy was established and the effects of temperature and strain rate on DFC were discussed. The results show that the variation range of DFC under different deformation conditions is 0.07–0.15. Subsequently, the deformation conditions with higher fracture risk were identified as 1200∼1275 K & 1∼10 s−1 and verified with the experiment observations.

scholarly journals HOT DEFORMATION BEHAVIOR AND PROCESSING MAP OF A Mg-Gd-Y-Zn-Zr ALLOY

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Zhaoming Yan ◽  
Jiaxuan Zhu ◽  
Zhimin Zhang ◽  
Qiang Wang ◽  
Yong Xue
Keyword(s):  
Strain Rate ◽  
Flow Behavior ◽  
Type Equation ◽  
Peak Stress ◽  
Material Model ◽  
Processing Parameters ◽  
Compression Tests ◽  
Hollomon Parameter ◽  
Dynamic Material Model ◽  
Deformation Behaviors

Compression tests of a Mg-13Gd-4Y-2Zn-0.5Zr alloy were carried out on a Gleeble-1500D thermo-mechanical simulator within a temperature range of 420–500 °C and strain rate of 0.001–5 s–1 so that the corresponding flow behavior was investigated. The Zener-Hollomon parameter Z was used in a hyperbolic-sine-type equation to express the relationships between the peak stress, deformation temperature and strain rate. Work hardening, dynamic recovery and dynamic recrystallization were the main characteristics affecting the plastic-deformation behaviors. The activation energy Q was calculated to be 208.2 kJ/mol and processing maps at strains of 0.3, 0.5 and 0.7 were generated based on a dynamic material model. The optimum processing parameters were obtained with a power-dissipation analysis.

scholarly journals Application of the Strain Compensation Model and Processing Maps for Description of Hot Deformation Behavior of Metastable β Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2021
Author(s):  
Oleksandr Lypchanskyi ◽  
Tomasz Śleboda ◽  
Aneta Łukaszek-Sołek ◽  
Krystian Zyguła ◽  
Marek Wojtaszek
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Flow Behavior ◽  
Microstructural Analysis ◽  
Calculated Data ◽  
Processing Temperature ◽  
Processing Maps ◽  
Compression Tests ◽  
Strain And Strain Rate ◽  
Average Absolute Relative Error

The flow behavior of metastable β titanium alloy was investigated basing on isothermal hot compression tests performed on Gleeble 3800 thermomechanical simulator at near and above β transus temperatures. The flow stress curves were obtained for deformation temperature range of 800–1100 °C and strain rate range of 0.01–100 s−1. The strain compensated constitutive model was developed using the Arrhenius-type equation. The high correlation coefficient (R) as well as low average absolute relative error (AARE) between the experimental and the calculated data confirmed a high accuracy of the developed model. The dynamic material modeling in combination with the Prasad stability criterion made it possible to generate processing maps for the investigated processing temperature, strain and strain rate ranges. The high material flow stability under investigated deformation conditions was revealed. The microstructural analysis provided additional information regarding the flow behavior and predominant deformation mechanism. It was found that dynamic recovery (DRV) was the main mechanism operating during the deformation of the investigated β titanium alloy.

Integrated AHP-BPNN Model for Wind Farm Investment Evaluation

2014 ◽  
Vol 541-542 ◽  
pp. 966-971
Author(s):  
Xiang Feng Zhang ◽  
Tian Yu Liu ◽  
Bin Jiao
Keyword(s):  
Wind Farm ◽  
Evaluation Method ◽  
Back Propagation ◽  
Wind Farms ◽  
Back Propagation Neural Network ◽  
Analytic Hierarchy ◽  
Farm Investment ◽  
Hierarchy Process ◽  
Power Project ◽  
Bpnn Model

The construction of wind farms grows quickly in China. It is necessary for stakeholders to estimate investment costs and to make good decisions about a wind power project by making a budget for the investment. This paper proposed an evaluation method by integrating the analytic hierarchy process (AHP) with back-propagation neural network (BPNN) to evaluate wind farm investment. In the AHP-BPNN model, the AHP method is used to determine the factors of wind farm investment. The factors with high importance are reserved while those with low importance are eliminated, which can decrease the number of inputs of the BPNN. The experiment results show that the integrated model is feasible and effective.

Critical Strain for the Initiation of Dynamic Recrystallization in a Ni-Fe Base Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 577-580
Author(s):  
Young Sang Na ◽  
Young Mok Rhyim ◽  
J.Y. Lee ◽  
Jae Ho Lee
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Critical Strain ◽  
Base Alloy ◽  
Strain Rate Range ◽  
Boundary Phase ◽  
Alloy 718 ◽  
Compression Tests ◽  
Temperature Range ◽  
Critical Strains

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 x 10-4s-1- 5 s-1with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ'' (matrix-hardening phase) and δ (grain boundary phase)on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.

A comparative study of different prediction models in predicting human resource demands

2021 ◽  
pp. 1-11
Author(s):  
Bo Huang
Keyword(s):  
Neural Network ◽  
Human Resources ◽  
Comparative Study ◽  
Human Resource ◽  
Prediction Models ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Prediction Methods ◽  
Bpnn Model ◽  
Good Agreement

This study analyzed three prediction models: ID model, GM (1,1) model and back-propagation neural network (BPNN) model. Firstly, the principles of the three models were introduced, and the prediction methods of the three models were analyzed. Then, taking enterprise A as an example, the demand for human resources was predicted, and the prediction results of the three models were compared. The results showed that the maximum and minimum errors were 240 people and 12 people respectively in the prediction results of the ID3 model and 64 people and 37 people respectively in the prediction results of the GM (1, 1) model; the errors of the BPNN model were smaller than ten people, and the minimum value of the BPNN model was three people, which was in good agreement with the actual value. The prediction of the human resource demand of enterprise A in the future five years with the BPNN model suggested that the demand for employees would growing rapidly. The results show that the BPNN model has better reliability and can be popularized and applied in practice.

Strain Rate Sensitivity of Ultrafine-Grained CP-Ti Processed by ECAP at Room Temperature

2010 ◽  
Vol 667-669 ◽  
pp. 707-712 ◽  
Author(s):  
Xiao Yan Liu ◽  
Xi Cheng Zhao ◽  
Xi Rong Yang
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Ultrafine Grained ◽  
Die Set ◽  
Increasing Temperature ◽  
Cp Ti

Ultrafine-grained (UFG) commercially pure (CP) Ti with a grain size of about 200 nm was produced by ECAP up to 8 passes using route BC at room temperature. For ECAP processing a proper die set was designed and constructed with an internal channel angle Φ of 120° and an outer arc of curvature Ψ of 20°. Strain rate sensitivity of UFG CP-Ti and CG CP-Ti were investigated by compression tests in the temperature range of 298~673K and strain rate range of 10-4~100s-1 using Gleeble simulator machine. Evolution of the microstructure during compression testing was observed using optical microscopy (OM) and transmission electron microscopy (TEM). Strain rate sensitivity value m of the UFG CP-Ti has been measured and is found to increase with increasing temperature and decreasing strain rate, and is enhanced compared to that of CG CP-Ti. Result of the deformation activation energy determination of UFG CP-Ti indicates that the deformation mechanism in UFG CP-Ti is correlated to the grain boundaries.

Characterization of Hot Deformation Behavior of Udimet720Li Superalloy Using Processing Map

2014 ◽  
Vol 887-888 ◽  
pp. 1161-1168
Author(s):  
Jian Guo Wang ◽  
Dong Liu ◽  
Tao Wang ◽  
Yan Hui Yang
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Flow Behavior ◽  
Strain Range ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Hot Working ◽  
Compression Tests ◽  
Hollomon Parameter

The deformation behavior of a Udimet720Li superalloy under hot compression tests was characterized in the temperature range of 1060~1160°C and strain rate range of 0.001~20s-1. Processing maps were conducted at a series of strains to calculate the efficiency of hot working and to recognize the instability regions of the flow behavior. A Zener-Hollomon parameter is given to characterize the dependence of peak stress on temperature and strain rate. The efficiency of power dissipation of the Udimet720Li superalloy obtained in a strain range of 0.1~0.7 are essentially similar, which indicates that strain does not have a significant influence and the instability region shown in high strain and high strain rates at all temperatures. The regions for the full recrystallization can be divided by the dissolution beginning temperature of primary γ'which are the optimum hot working parameters.

Hot Deformation Behaviors of SiCp/Al Composites

2014 ◽  
Vol 1058 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Ming Hao ◽  
Jing Pei Xie
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
True Strain ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Tests ◽  
Sensitive Material ◽  
2024 Aluminum Alloy ◽  
Deformation Behaviors

The hot deformation behaviors of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500 thermomechanical simulator at temperatures ranging from 350-500°C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 183.251 kJ/mol. The optimum hot working conditions for this material are suggested.

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