Constitutive Modeling of Beta Titanium Alloy Ti-10V-4.5Fe-1.5Al during Hot Deformation Process

2012 ◽  
Vol 510 ◽  
pp. 729-733
Author(s):  
Feng Bo Han ◽  
Jin Shan Li ◽  
Hong Chao Kou ◽  
Bin Tang ◽  
Min Jie Lai ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Dislocation Density ◽  
Internal State ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Model Parameters ◽  
Internal State Variable ◽  
Dislocation Interaction ◽  
State Variable

A constitutive model using dislocation density rate as an internal state variable has been proposed for hot working of β titanium alloy in this paper. The β phase was only taken into consideration during high temperature deformation. The solution strengthening and dislocation interaction were included in the constitutive equations. The strength coefficient was determined by equivalent vanadium content, Veq, which was calculated according to the alloy constituent. A Kocks-Mecking model was adopted to describe the variation of dislocation density. The constitutive relationship of a β titanium alloy Ti-10V-4.5Fe-1.5Al for high temperature deformation was established using the internal-state-variable based model. Model parameters were determined by the genetic algorithm based objective optimization method. The predicted results agree fairly well with the experimental value.

Estimation of Back Stress Produced by Dislocation Interaction in Icosahedral Al-Pd-Mn

2000 ◽  
Vol 643 ◽  
Author(s):  
Hisatoshi Hirai ◽  
Akira Kitahara ◽  
Fuyuki Yoshida ◽  
Hideharu Nakashima
Keyword(s):  
Shear Stress ◽  
High Temperature ◽  
Main Part ◽  
Unit Length ◽  
Back Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Dislocation Interaction ◽  
Burgers Vector ◽  
Phonon Component

AbstractWe attempted to calculate the breakaway stress σb of dislocation from attractive junction made by reaction of dislocations. Assuming that the force f acting on the unit length of dislocation with the Burgers vector B under a shear stress τa is f τ∣b˝∣ where b˝ is the phonon component of B, and that the elastic energy per unit length of dislocation W is approximated by W = G(∣b˝∣2 + c2 ∣b˔∣2) where G is the shear modulus, b˔ the phason component of B and c2 a coefficient of about 3.1 × 10−3. Using the values G = 48.4 GPa at 1070 K, the Taylor factor M = 3 and the measured dislocation density of 1.8 × 1013 m−2, we calculated σb for 21 possible dislocation reactions. Picking up the most possible dislocation reactions, σb distributed between 50 and 80 MPa, and the average of them was 64 MPa. This result strongly suggested the possibility that the main part of the internal stress of the high-temperature deformation of icosahedral Al-Pd-Mn is explained by σb.

scholarly journals High-Temperature Flow Behaviour and Constitutive Equations for a TC17 Titanium Alloy

2019 ◽  
Vol 38 (2019) ◽  
pp. 168-177 ◽  
Author(s):  
Liu Shi-feng ◽  
Shi Jia-min ◽  
Yang Xiao-kang ◽  
Cai Jun ◽  
Wang Qing-juan
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Constitutive Equation ◽  
Constitutive Equations ◽  
Deformation Behaviour ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Average Absolute Relative Error ◽  
Wide Range

AbstractIn this study, the high-temperature deformation behaviour of a TC17 titanium alloy was investigated by isothermal hot compression tests in a wide range of temperatures (973–1223 K) and strain rates (0.001–10 s−1). Then, the constitutive equations of different phase regimes (α + β and single β phases) were developed on the basis of experimental stress-strain data. The influence of the strain has been incorporated in the constitutive equation by considering its effect on different material constants for the TC17 titanium alloy. Furthermore, the predictability of the developed constitutive equation was verified by the correlation coefficient and average absolute relative error. The results indicated that the obtained constitutive equations could predict the high-temperature flow stress of a TC17 titanium alloy with good correlation and generalization.

203 High temperature deformation characteristic of α+β titanium alloy sheet

2015 ◽  
Vol 2015.53 (0) ◽  
pp. _203-1_-_203-2_
Author(s):  
Shogo MATSUI ◽  
Yoshihisa SHIRAI ◽  
Fusahito YOSHIDA ◽  
Hiroshi HAMASAKI
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Deformation Characteristic ◽  
Alloy Sheet ◽  
High Temperature Deformation ◽  
Temperature Deformation

Modelling Dynamic Recovery and Recrystallization of Metals by a New Non-Equilibrium Thermodynamics Approach

2007 ◽  
Vol 558-559 ◽  
pp. 517-522
Author(s):  
Ming Xin Huang ◽  
Pedro E.J. Rivera-Díaz-del-Castillo ◽  
Sybrand van der Zwaag
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Flow Stress ◽  
Dislocation Density ◽  
Dynamic Recovery ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Equilibrium Thermodynamics ◽  
Burgers Vector ◽  
Non Equilibrium

A non-equilibrium thermodynamics-based approach is proposed to predict the dislocation density and flow stress at the steady state of high temperature deformation. For a material undergoing dynamic recovery and recrystallization, it is found that the total dislocation density can be expressed as ( )2 ρ = λε& b , where ε& is the strain rate, b is the magnitude of the Burgers vector and λ is a dynamic recovery and recrystallization related parameter.

Temperature-Dependent Fracture Mechanics-Informed Damage Model for Ceramic Matrix Composites

2021 ◽  
Author(s):  
Travis Skinner ◽  
Aditi Chattopadhyay
Keyword(s):  
Fracture Mechanics ◽  
Internal State ◽  
Damage Model ◽  
Ceramic Matrix ◽  
Model Parameters ◽  
Internal State Variable ◽  
Temperature Dependent ◽  
State Variable ◽  
Initiation And Propagation ◽  
Matrix Damage

Abstract This work presents a temperature-dependent reformulation of a multiscale fracture mechanics-informed matrix damage model previously developed by the authors. In this paper, internal state variable theory, fracture mechanics, and temperature-dependent material properties and model parameters are implemented to account for length scale-specific ceramic matrix composite (CMC) brittle matrix damage initiation and propagation behavior for temperatures ranging from room temperature (RT) to 1200°C. A unified damage internal state variable (ISV) is introduced to capture effects of matrix porosity, which occurs as a result of material diffusion around grain boundaries, as well as matrix property degradation due to matrix crack initiation and propagation. The porosity contribution to the unified damage ISV is related to the volumetric strain, and matrix cracking effects are captured using fracture mechanics and crack growth kinetics. A combination of temperature-dependent material properties and damage model parameters are included in the model to simulate effects of temperature on the deformation and damage behavior of 2D woven C/SiC CMC material systems. Model calibration is performed using experimental data from literature for plain weave C/SiC CMC at RT, 700°C, and 1200°C to determine how damage model parameters change in this temperature range. The nonlinear, temperature-dependent predictive capabilities of the reformulated model are demonstrated for 1000°C using interpolation to obtain expected damage model parameters at this temperature and the predictions are in good agreement with experimental results at 1000°C.

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