A Study on Crystal Slip and Grain Rotation of FCC Metals Based on Strain-Rate Type Constitutive Equation

1989 ◽  
pp. 601-604 ◽  
Author(s):  
T. Abe ◽  
M. Yamada ◽  
S. Nagaki
Author(s):  
Habib Ramezannejad Azarboni ◽  
Abolfazl Darvizeh

The effect of strain rate on the cavitation time and elastoplastic deformation of steel rectangular plate subjected to underwater explosion load is analytically and numerically investigated in this study. At the cavitation time, the total pressure of the explosion is eliminated so that the cavitation time plays a significant role in the elastoplastic deformation of underwater explosive forming of plate. Taking into account the strain rate effect, the Cowper-Symond constitutive equation of mild steel is employed. Exact linear solution using the Eigen function and numerical linear and nonlinear solution using finite difference method (FDM) of dynamic response of impulsively plate is obtained. Implementing the linear work hardening, the stress, strain, displacement, and velocity in any steps of loading are calculated. The time of cavitation can be recognized in elastic or plastic regimes by applying the Cowper-Symond constitutive equation. Considering the strain rate influence, the effects of charge mass and standoff are investigated to occur of cavitation and time dependent deflection and velocity of a rectangular plate.


2006 ◽  
Vol 503-504 ◽  
pp. 31-36 ◽  
Author(s):  
Johannes Mueller ◽  
Karsten Durst ◽  
Dorothea Amberger ◽  
Matthias Göken

The mechanical properties of ultrafine-grained metals processed by equal channel angular pressing is investigated by nanoindentations in comparison with measurements on nanocrystalline nickel with a grain size between 20 and 400 nm produced by pulsed electrodeposition. Besides hardness and Young’s modulus measurements, the nanoindentation method allows also controlled experiments on the strain rate sensitivity, which are discussed in detail in this paper. Nanoindentation measurements can be performed at indentation strain rates between 10-3 s-1 and 0.1 s-1. Nanocrystalline and ultrafine-grained fcc metals as Al and Ni show a significant strain rate sensitivity at room temperature in comparison with conventional grain sized materials. In ultrafine-grained bcc Fe the strain rate sensitivity does not change significantly after severe plastic deformation. Inelastic effects are found during repeated unloading-loading experiments in nanoindentations.


2021 ◽  
Vol 1035 ◽  
pp. 189-197
Author(s):  
Bao Ying Li ◽  
Bao Hong Zhu

The hot deformation behavior of spray-formed AlSn20Cu alloy during hot compression deformation was studied, and the constitutive equation of AlSn20Cu alloy was established. The samples of spray-formed AlSn20Cu alloy were compressed on Gleeble-3500 thermal simulation test machine. The error of the true stress caused by adiabatic heating effect in the experiment was corrected. The constitutive equation of spray-formed AlSn20Cu alloy could be represented by Zener-Hollomon parameter in a hyperbolic sine function. The results showed that the deformation temperatures and strain rates had a notable effect on the true stress of the alloy. At the identical deformation temperature, the true stress increased with the increase of strain rate. When the strain rate was constant, the stress decreased with the increase of deformation temperature. After hot compression deformation, the tin phase was elongated along the direction perpendicular to the compression axis with short strips and blocks. With the increase of deformation temperature and the decrease of strain rate, Sn phase distribution became more homogeneous.


Author(s):  
E Etemadi ◽  
J Zamani ◽  
M Jafarzadeh

This paper develops a new physically based model to investigate face centered cubic (FCC) metals and alloys under high strain rate loadings (\gt104 s−1) which includes kinematics and constitutive equations for the propagation of elastic and steady plastic waves. The model’s formulations are based on the rate of the conservation energy law that includes the rate of the input energy, internal energy, and entropy generation. This formulation is obtained by incorporating the viscous drag effects and associating the entropy generation to the generation, glide, and annihilation of dislocations. The model is used for 6061-T6 aluminum alloys and the results are verified with the published theoretical models and experimental tests. Also, the effect of different parameters, such as the particle velocity, shear flow stress, shear strain rate and temperature are investigated. As a result, the presented model shows good capability in describing the mentioned parameters.


2017 ◽  
Vol 36 (7) ◽  
pp. 701-710
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Xiaolu Zhang ◽  
Wen Wang

AbstractHigh temperature deformation behavior of BFe10-1-2 cupronickel alloy was investigated by means of isothermal compression tests in the temperature range of 1,023~1,273 K and strain rate range of 0.001~10 s–1. Based on orthogonal experiment and variance analysis, the significance of the effects of strain, strain rate and deformation temperature on the flow stress was evaluated. Thereafter, a constitutive equation was developed on the basis of the orthogonal analysis conclusions. Subsequently, standard statistical parameters were introduced to verify the validity of developed constitutive equation. The results indicated that the predicted flow stress values from the constitutive equation could track the experimental data of BFe10-1-2 cupronickel alloy under most deformation conditions.


2013 ◽  
Vol 816-817 ◽  
pp. 84-89
Author(s):  
Yong Gang Kang ◽  
Yuan Yang ◽  
Jie Huang ◽  
Jing Hang Zhu

7075-T651 aluminum alloy are widely used in aeronautical applications such as wing panels, but there is no corresponding constitutive model for it now. In this paper, the flow behavior of 7050-T651 aluminum alloy was investigated by Split Hopkinson Pressure Bar (SHPB) and quasi-static compression experiment system. The strain hardening parameters were obtained by quasi-static compression experiment data, and the strain rate hardening parameters at various strain rates (1000-3000s-1) and room temperature, and the thermal softening parameter at various temperatures (20-300°C) where strain rate is 3000s-1 were obtained by SHPB experiment data. Then the constitutive equation of 7075-T651 aluminum alloy is obtained based on Johnson-Cook constitutive equation model.


Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2020
Author(s):  
Baoquan Mao ◽  
Rui Zhu ◽  
Zhiqian Wang ◽  
Yuying Yang ◽  
Xiaoping Han ◽  
...  

To better describe its constitutive relation, we need a new constitutive equation for an important nonlinear elastic material, Mn-Cu damping alloy. In this work, we studied the nonlinear and hysteretic characteristics of the stress-strain curve of the M2052 alloy with the uniaxial cyclic tensile test with constant strain rate. The strain rate and amplitude correlations of M2052 resembled those of nonlinear viscoelastic material. Therefore, we created a new constitutive equation for the M2052 damping alloy by modifying the fractional Maxwell model, and we used the genetic algorithm to carry out numerical fitting with MATLAB. By comparing with the experimental data, we confirmed that the new constitutive equation could accurately depict the nonlinear constitutive relation and hysteretic property of the damping alloy. Taken together, this new constitutive equation for Mn-Cu damping alloy based on the fractional Maxwell model can serve as an effective tool for further studies of the constitutive relation of the Mn-Cu damping alloys.


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