Effect of Deformation Temperature, Strain Rate and Strain on the Strain Hardening Exponent of Copper/Aluminum Laminated Composites

2018 ◽  
Vol 27 (4) ◽  
pp. 096369351802700 ◽  
Author(s):  
Shuaiyang Liu ◽  
Aiqin Wang ◽  
Jingpei Xie

In order to investigate the strain hardening behaviour of Cu/Al laminated composites, isothermal compression tests were conducted in the temperature range of 300–450 °C and stain rate range of 0.01–1 s−1. Based on the experimental data, stain hardening exponent n was calculated to evaluate the strain hardening ability of Cu/Al laminated composites during the deformation process. The results show that deformation temperature, strain rate, strain and laminated structure are all responsible for the evolution of flow stress during the isothermal compression. The highly non-linear character of Ln σ - Ln ε curves shows the dynamic competition between work hardening and dynamic softening, and dynamic softening gradually plays a dominant role with the increase of strain. Furthermore, strain hardening exponent n is more sensitive to deformation temperature than strain rate. Lower deformation temperature and higher strain rate contribute to the enhancement of strain hardening exponent n.

Author(s):  
Shuaiyang Liu ◽  
Aiqin Wang ◽  
Tingting Liang ◽  
Jingpei Xie

In order to understand the hot deformation behavior of novel Cu/Al laminated composites, isothermal hot compression tests were conducted by Gleeble-1500D thermo-mechanical simulator. And the effect of bonding interface, deformation temperature and strain rate on the deformation behavior was analyzed. Results show that under the interface constraint effect, soft Al layer trends to flow synchronously with hard Cu layer. And further microstructure examinations indicate the cooperative deformation capability of Cu/Al composites increases with increasing stain rate and decreasing deformation temperature. Strain hardening exponent, calculated based on the true stress-true strain data, also proves the effect of deformation temperature and strain rate on the cooperative deformation behavior. Meanwhile, unique composites structure allows the Al matrix to exhibit the characteristic of dynamic recrystallization during the hot deformation process. Lastly, strain compensated Arrhenius-type constitutive equation was employed to describe the coupling effect of temperature, strain rate and strain on the flow stress.


1968 ◽  
Vol 35 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Norman Jones

A relatively simple analytical treatment of the behavior of a rigid-plastic annular plate subjected to an initial linear impulsive velocity profile is presented. The influence of finite deflections has been included in addition to strain-hardening and strain-rate sensitivity of the plate material. It is shown, for deflections up to the order of twice the plate thickness, that strain-hardening is unimportant, strain-rate sensitivity has somewhat more effect, while membrane forces play a dominant role in reducing the permanent deflections.


Author(s):  
Aly El Domiaty ◽  
Abdel-Hamid I. Mourad ◽  
Abdel-Hakim Bouzid

One of the most significant approaches for predicting formability is the use of forming limit diagrams (FLDs). The development of the generalized model integrates other models. The first model is based on Von-Misses yield criterion (traditionally used for isotropic material) and power law constitutive equation considering the strain hardening exponent. The second model is also based on Von-Misses yield criterion but uses a power law constitutive equation that considers the effect of strain rate sensitivity factor. The third model is based on the modified Hill’s yield criterion (for anisotropic materials) and a power law constitutive equation that considers the strain hardening exponent. The current developed model is a generalized model which is formulated on the basis of the modified Hill yield criterion and a power law constitutive equation considering the effect of strain rate. A new controlling parameter (γ) for the limit strains was exploited. This parameter presents the rate of change of strain rate with respect to strain. As γ increases the level of the FLD raises indicating a better formability of the material.


2012 ◽  
Vol 430-432 ◽  
pp. 256-259 ◽  
Author(s):  
Yang Yang ◽  
Chun Fu Li ◽  
Kai Hong Song

TWIP steel containing 0.21% C, 24.4% Mn, 0.9% Si, 1.84% Al, 4.61% Cr, 1.89% Ni, 0.41% Mo and 0.012% Nb was investigated. Tensile tests of this steel were performed in the strain rate range of 10−4–10−3 s−1. Results indicate that tensile properties of TWIP steel at room temperature are sensitive to strain rate in the studied range. Analyses on the relationship between strain–hardening exponent and strain rates show that the formation of twins during deformation greatly affects the strain–hardening behavior of TWIP steels.


2008 ◽  
Vol 22 (09n11) ◽  
pp. 1221-1227
Author(s):  
JIN-YOUNG KIM ◽  
IN-OK SHIM ◽  
SOON-HYUNG HONG

The effects of microstructures of Ti -6 Al -4 V alloy on the flow stresses and fracture behaviors at quasi-static and dynamic deformation conditions were investigated. Specimens of different sizes and fractions of α globules in equiaxed and bimodal structures were compressed at the strain rate of 2×10−3/ s and 3×103/ s using hydraulic testing machine and split Hopkinson pressure bar, respectively. The a globule size in equiaxed structure changed the level of flow stresses, but did not affect the strain hardening characteristics. Meanwhile, the volume fraction of α globule (or lamellar phase) in bimodal structures influenced both the flow stress and strain hardening exponent at quasi-static and dynamic deformation conditions. Bimodal structure of 50% lamellar fraction is considered to be more favorable in dynamic deformation condition at strain rate regime of 3×103/ s than equiaxed or bimodal one having higher lamellar fraction.


2018 ◽  
Vol 777 ◽  
pp. 402-407
Author(s):  
Gui Qing Chen ◽  
Gao Sheng Fu ◽  
Xiao Dong Lin ◽  
Jun De Wang ◽  
Chao Zeng Cheng ◽  
...  

3003 aluminum melt was treated with efficient purification, and it was deformed by isothermal compression in the range of deformation temperature 300-500 °C at strain rate 0.0l-10.0 s-1 with Gleeble-1500 thermal simulator. The results show that efficient purification treatment can significantly reduce the impurities, and make inclusion size smaller, uniform distribution. Room temperature mechanical properties were significantly improved. At the same strain rate, the flow stress of 3003 aluminum alloy decreases with the increase of deformation temperature. The flow stress increases with the increase of strain rate under the same deformation temperature. Two kinds of 3003 aluminum alloys with different purification treatments both have dynamic recrystallization characteristics. Especially when the strain rate reaches 10.0 s-1, the rheological curve appears sawtooth fluctuation and the alloy may have discontinuous dynamic recrystallization.


2007 ◽  
Vol 546-549 ◽  
pp. 749-754 ◽  
Author(s):  
Hui Zhong Li ◽  
Xin Ming Zhang ◽  
Min Gan Chen ◽  
Ying Liu ◽  
Hui Gao

The deformation behavior of 2519 aluminum alloy was studied by isothermal compression by Gleeble-1500 simulator in the temperature range from 300 to 450°C under the strain rates of 0.01~10s-1. The results showed that the flow stress was controlled by strain rate and deformation temperature. The flow stress increased with strain rate and decreased with deformation temperature. The flow stress of 2519 aluminum alloy increased with strain and to the constant values at three strain rates of 0.01 s-1,0.1 s-1and1 s-1, indicating the dynamic recovery to occur. The flow stress decreased after a peak value with increase of strain at strain rate 10s-1 and deformation temperature higher than 350°C, showing partly dynamic recrystallization. The flow stress of 2519 aluminum alloy during high temperature deformation can be represented by Zener-Hollomon parameter.


Sign in / Sign up

Export Citation Format

Share Document