High-Strain-Rate Response of a Specially-Made Copper Sample

2015 ◽  
Vol 817 ◽  
pp. 35-41
Author(s):  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie ◽  
Wei Bin Xie ◽  
Yang Li ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Temperatures ◽  
High Strain ◽  
Copper Sample ◽  
Dislocation Slip ◽  
Softening Effect ◽  
Hardening Effect ◽  
Dynamic Recrystallization Behavior ◽  
Strain Rate Hardening

In the present study, a systematic study on both the high strain-rate tensile and compressive deformation behaviors of a specially-made copper sample have been carried out at different high temperatures, by using the split Hopkinson bar experiments. The Johnson-Cook constitutive model was used to model the high strain-rate responses of the specimen at high temperatures. The results showed that compared with other metallic materials, the specially-made copper sample had a relatively stronger strain-rate-hardening effect and weaker temperature-softening effect. Evolution of the microstructure suggests that under high strain-rate, both the dislocation slip and deformation twins contribute to the plastic strengthening of the copper specimen, resulting in the strain-rate-hardening effect. And the dynamic recrystallization behavior plays an important role during the high strain-rate deformation process at the high temperatures.

High Temperature High Strain-Rate Tensile and Compressive Deformation Behaviors of Cu-Zn-Sn-Al Alloy

2015 ◽  
Vol 817 ◽  
pp. 55-62
Author(s):  
Qiang Song Wang ◽  
Dong Mei Liu ◽  
Guo Liang Xie ◽  
Wei Bin Xie ◽  
Yang Li ◽  
...  
Keyword(s):  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Al Alloy ◽  
Softening Effect ◽  
Α Phase ◽  
Hardening Effect ◽  
Deformation Behaviors ◽  
Strain Rate Hardening

The present work gives a systematic study on the high temperature and high strain-rate deformation behaviors of a two-phase α/β Cu-Zn-Sn-Al alloy, by combining the split Hopkinson bar experiments and microstructural investigations. The results show that under high strain-rate, both the dislocation slip and deformation twins within the α phase contribute to the plastic strengthening of Cu-Zn-An-Al alloy, resulting in the strain-rate-hardening effect. As the deformation temperature increases, the shapes of the stress-strain curves are mainly influenced by the temperature-softening effect and the dynamic recrystallization of the α phase. Finally, material constants regarding the strain-rate-hardening and temperature-softening effects are determined, based on the Johnson-Cook constitutive model. The results show that compared with other metallic materials, the present Cu-Zn-Sn-Al alloy has a relatively stronger strain-rate-hardening effect and weaker temperature-softening effect.

Study on Dynamic Mechanical Response of TC21 Alloy

2011 ◽  
Vol 88-89 ◽  
pp. 674-678
Author(s):  
Shuang Zan Zhao ◽  
Xing Wang Cheng ◽  
Fu Chi Wang
Keyword(s):  
Flow Stress ◽  
High Strain Rate ◽  
Strain Rate ◽  
Strain Hardening ◽  
High Strain ◽  
Dynamic Flow ◽  
Dynamic Mechanical ◽  
Hardening Effect ◽  
High Strain Rate Deformation ◽  
Binary Morphology

Some results of an experimental study on high strain rate deformation of TC21 alloy are discussed in this paper. Cylindrical specimens of the TC21 alloys both in binary morphology and solution and aging morphology were subjected to high strain rate deformation by direct impact using a Split Hopkinson Pressure Bar. The deformation process is dominated by both thermal softening effect and strain hardening effect under high strain rate loading. Thus the flow stress doesn’t increase with strain rate at the strain hardening stage, while the increase is obvious under qusi-static compression. Under high strain rate, the dynamic flow stress is higher than that under quasi-static and dynamic flow stress increase with the increase of the strain rate, which indicates the strain rate hardening effect is great in TC21 alloy. The microstructure affects the dynamic mechanical properties of TC21 titanium alloy obviously. Under high strain rate, the solution and aging morphology has higher dynamic flow stress while the binary morphology has better plasticity and less prone to be instability under high strain rate condition. Shear bands were found both in the solution and aging morphology and the binary morphology.

High Strain Rate Superplasticity and Microstructure Evolution in a Coarse-Grained Mg-Gd-Y-Zr Rolled Sheet

2014 ◽  
Vol 900 ◽  
pp. 719-724
Author(s):  
Ying Zheng ◽  
Chang Ping Tang ◽  
Yun Lai Deng
Keyword(s):  
Electron Microscopy ◽  
Dynamic Recrystallization ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Microstructural Analysis ◽  
Alloy Sheet ◽  
Coarse Grained ◽  
Dislocation Slip ◽  
Rolled Sheet

Superplasticity at high deformation rates is desirable in order to make superplastic forming more practical. High strain rate superplastic behavior and microstructure of the rolled Mg-Gd-Y-Zr alloy sheet were investigated. For the purposes, tensile tests at the strain rate of 0.01 s-1were conducted, which revealed that the sheet exhibited elongations of 180%~266%. Post-deforming microstructures were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, while crystallographic orientation information was obtained from macro-texture analysis. The results show that the high strain rate superplasticity was attributed to class-I creep accommodated by dynamic recrystallization. It is suggested from microstructural analysis results that the interaction between second phases and dislocation facilitated dynamic recrystallization. The macro-texture at the strain of 0.8 still exhibited some characteristics of the crystal rotation arising from dislocation slip despite the occurrence of DRX.

Effect of Strain Rate on Mechanical Properties of Fe-30Mn-3Si-4Al TWIP Steel

2012 ◽  
Vol 581-582 ◽  
pp. 1018-1022 ◽  
Author(s):  
Zhi Ping Xiong ◽  
Lei Gang Gu ◽  
Ye Ke Wang ◽  
Ji Cheng Zhao ◽  
Wei Ping Bao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Twip Steel ◽  
High Strain ◽  
Rate Sensitivity ◽  
Strain Hardening Exponent ◽  
Softening Effect ◽  
Adiabatic Temperature Rise ◽  
Softening Stage

Influence of strain rate on mechanical properties of Fe-30Mn-3Si-4Al TWIP steel was studied by compression experiments, indicating that TWIP steel has strain rate softening effect, strain rate insensitivity, and also strain rate hardening effect. According to strain rate sensitivity m changing with strain rate, effect of strain rate on TWIP steel mechanical properties can be divided into three stages: quasi-static stage with strain rate ranging from 0.001 to 100 1/s; high-strain rate stage with strain rate ranging from 701 to 5108 1/s; super-high-strain rate stage with strain rate ranging from 10335 to 30147 1/s. Adiabatic temperature rise tends to increase with strain rate. Strain hardening exponent is divided into three parts: dislocation strengthening stage, twinning strengthening stage and thermal softening stage.

High strain rate response of S355 at high temperatures

2016 ◽  
Vol 94 ◽  
pp. 467-478 ◽  
Author(s):  
Daniele Forni ◽  
Bernardino Chiaia ◽  
Ezio Cadoni
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Temperatures ◽  
High Strain

An Investigation on High Strain Rate Superplasticity of an Al-Cu-Mg-Ti-Sr Ingot Alloy

2004 ◽  
Vol 471-472 ◽  
pp. 692-696
Author(s):  
Xiao Jing Xu ◽  
Lan Cai ◽  
Seock Sam Kim
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
High Strain ◽  
Tensile Elongation ◽  
Rate Sensitivity ◽  
Hot Extrusion ◽  
Initial Strain Rate ◽  
Grain Boundary Sliding ◽  
Dislocation Slip

An ingot aluminum alloy (Al-Cu-Mg-Ti-Sr) with high strength and high strain rate superplasticity has been successfully developed through a conventional manufacture route consisting of casting, heat treatment, hot extrusion with a low extrusion rate of only 10:1, hot-rolling and further cold-rolling, which is cost effective and suitable for large volume production industries. The tensile test result showed the alloy possesses not only a high ultimate strength of 513.85MPa at room temperature, but also a good high strain rate superplasticity with the tensile elongation of 174~224%, the flow stress of 17.1~33.9MPa and the strain rate sensitivity m-value of 0.174~0.293 in the initial strain rate of 3.16×10-2~1.0×10-1s-1 and at the temperature of 748K~793K. Differential scanning calorimeter (DSC) analysis showed that the superplastic deformation has no relationship with liquid phase. Scanning electron microscopy (SEM) analysis of fracture surface and surface showed that the superplastic deformation results from fine grain boundary sliding and dislocation slip.

scholarly journals Effect of the Strain Rate on the Damping and Mechanical Properties of a ZK60 Magnesium Alloy

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2969 ◽  
Author(s):  
Xuhui Feng ◽  
Youping Sun ◽  
Yuwei Lu ◽  
Jiangmei He ◽  
Xiao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Magnesium Alloy ◽  
Dislocation Density ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Temperatures ◽  
High Strain ◽  
Damping Capacity ◽  
Zk60 Magnesium Alloy

High strain rate rolling (HRSS) of a ZK60 magnesium alloy at 300 °C with a strain rate from 5 s−1 to 25 s−1 was used to research the effect of the rate on the mechanical properties and damping capacity of the ZK60 alloy. The results show that as the strain rate increases, the tensile strength decreases from 355 MPa at 25 s−1 to 310 MPa at 5 s−1. Two damping peaks (P1 and P2) are detected in the high strain rate rolled ZK60 alloys at different strain rates. The P1 peak appears at low temperatures and is caused by grain boundaries sliding. The P2 peak appears at high temperatures and is caused by recrystallization. As the strain rate increases from 5 to 20 s−1, the dynamic recrystallization (DRX) volume percent rises and the dislocation density decreases, both of which cause the P1 peak to become more and more obvious, and activation energy rises. At the same time, the dislocation density decreases and leads to a decrease in the storage energy, which reduces the recrystallization driving force and shifts the P2 peak to high temperatures. When the strain rate reaches 20 and 25 s−1, DRX occurs fully in the sheet, so the activation energy of the P1 peak and the temperature where the P2 peak appears are basically equal.

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