Abnormal strain rate strengthening and strain hardening with constitutive modeling in body-centered cubic {332} TWIP titanium alloy

2022 ◽  
pp. 117641
Author(s):  
Kai Yao ◽  
Xiaohua Min
Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2021
Author(s):  
Oleksandr Lypchanskyi ◽  
Tomasz Śleboda ◽  
Aneta Łukaszek-Sołek ◽  
Krystian Zyguła ◽  
Marek Wojtaszek

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.


Author(s):  
Sijia Zhong ◽  
Jianfeng Shi ◽  
Jinyang Zheng

Polyethylene (PE) pipes have been applied in transportation of key energy medium such as natural gas in the past decades. The mechanical property of PE is of great importance for better design and safer application of PE pipeline system. The large deformation behavior is a key character of PE, not only for its significant strain rate sensitivity, but also for localized necking process after yielding. In this paper, a new constitutive modeling method was proposed to charaterize the rate-denpendent large deformation behavior of PE, in which the true stress is regarded as a function of true stain and true strain rate alone. Uniaxial tensile tests of PE were conducted under various cross-head speeds, and a digital camera was used to record the real-time deformation of specimens. By separating the composite effect into respective effect of local true strain and strain rate on the local true stress in the necking region, a phenomenological model for describing the rate-dependent deformation behavior under uniaxial tension was ealstablished. Model results were validated and found in good agreement with experimental data.


Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1088 ◽  
Author(s):  
Yang Kang ◽  
Dunhong Zhou ◽  
Qiang Wu ◽  
Fuyan Duan ◽  
Rufang Yao ◽  
...  

The physical properties—including density, glass transition temperature (Tg), and tensile properties—of polybutadiene (PB), polystyrene (PS) and poly (styrene-butadiene-styrene: SBS) block copolymer were predicted by using atomistic molecular dynamics (MD) simulation. At 100 K, for PB and SBS under uniaxial tension with strain rate ε ˙ = 1010 s−1 and 109 s−1, their stress–strain curves had four features, i.e., elastic, yield, softening, and strain hardening. At 300 K, the tensile curves of the three polymers with strain rates between 108 s−1 and 1010 s−1 exhibited strain hardening following elastic regime. The values of Young’s moduli of the copolymers were independent of strain rate. The plastic modulus of PS was independent of strain rate, but the Young’s moduli of PB and SBS depended on strain rate under the same conditions. After extrapolating the Young’s moduli of PB and SBS at strain rates of 0.01–1 s−1 by the linearized Eyring-like model, the predicted results by MD simulations were in accordance well with experimental results, which demonstrate that MD results are feasible for design of new materials.


Author(s):  
Christopher B. Finfrock ◽  
Melissa M. Thrun ◽  
Diptak Bhattacharya ◽  
Trevor J. Ballard ◽  
Amy J. Clarke ◽  
...  

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