Rate sensitivity and deformation mechanism of semi‐crystalline polymers during instrumented indentation

2021 ◽  
Author(s):  
Erqiang Liu ◽  
Jianguo Wu ◽  
Huaying Li ◽  
Haitao Liu ◽  
Guanghui Zhao ◽  
...  
Keyword(s):  
Deformation Mechanism ◽  
Rate Sensitivity ◽  
Instrumented Indentation ◽  
Crystalline Polymers

Evolution of plasticity, strain-rate sensitivity and the underlying deformation mechanism in Zn–22% Al during high-pressure torsion

2014 ◽  
Vol 75 ◽  
pp. 102-105 ◽  
Author(s):  
In-Chul Choi ◽  
Yong-Jae Kim ◽  
Byungmin Ahn ◽  
Megumi Kawasaki ◽  
Terence G. Langdon ◽  
...  
Keyword(s):  
High Pressure ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Deformation Mechanism ◽  
High Pressure Torsion ◽  
Rate Sensitivity

DEFORMATION MECHANISM OF BULK NANOCRYSTALLINE NI PREPARED BY PLASMA EVAPORATION METHOD

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1640-1645 ◽  
Author(s):  
JIANQIU ZHOU ◽  
RONGTAO ZHU ◽  
ZHENZHONG ZHANG
Keyword(s):  
Deformation Mechanism ◽  
Rate Sensitivity ◽  
Bulk Sample ◽  
Evaporation Method ◽  
Dislocation Glide ◽  
Before And After ◽  
Bulk Nanocrystalline ◽  
Evolution Of Microstructure ◽  
Strength And Ductility ◽  
Main Operating

Bulk nanocrystalline Ni samples were prepared by plasma evaporation method combined with hot pressure sintering. The compressive mechanical properties of the bulk samples were tested under quasi-static strain rates at room temperature and the evolution of microstructure of bulk sample before and after compression was studied. The experimental results indicated that the bulk samples show a good combination of strength and ductility and have obvious strain rate sensitivity. Both dislocation glide mediated and grain boundary mediated deformation mechanism were found to be main operating deformation mechanisms for the bulk samples based on the mechanical behaviors and grain refinement after compression.

scholarly journals Rheological Law and Mechanism for Superplastic Deformation of Ti–6Al–4V

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3520
Author(s):  
Chao Liu ◽  
Ge Zhou ◽  
Xin Wang ◽  
Jiajing Liu ◽  
Jianlin Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Deformation Mechanism ◽  
Superplastic Deformation ◽  
Rate Sensitivity ◽  
Material Model ◽  
Sensitivity Index ◽  
Compression Tests ◽  
Dynamic Material Model ◽  
Strain Rate Sensitivity Index ◽  
Evolution Laws

The behaviors of and mechanisms acting in Ti–6Al–4V alloy during low-temperature superplastic deformation were systematically studied by using a Gleeble-3800 thermocompression simulation machine. Focusing on the mechanical behaviors and microstructure evolution laws during low-temperature superplastic compression tests, we clarified the changing laws of the strain rate sensitivity index, activation energy of deformation, and grain index at varying strain rates and temperatures. Hot working images based on the dynamic material model and the deformation mechanism maps involving dislocation quantity were plotted on the basis of PRASAD instability criteria. The low-temperature superplastic compression-forming technique zone and the rheological instability zone of Ti–6Al–4V were analyzed by using hot processing theories. The dislocation evolution laws and deformation mechanisms of the grain size with Burgers vector compensation and the rheological stress with modulus compensation during the low-temperature superplastic compression of Ti–6Al–4V were predicted by using deformation mechanism maps.

Rate-change instrumented indentation for measuring strain rate sensitivity

2009 ◽  
Vol 24 (4) ◽  
pp. 1466-1470 ◽  
Author(s):  
D. Pan ◽  
M.W. Chen
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
High Strength ◽  
Rate Change ◽  
Instrumented Indentation ◽  
Rate Dependent ◽  
Self Consistency

A rate-change instrumented indentation method is introduced to experimentally characterize the strain rate sensitivity of high strength materials, such as metallic glasses and nanocrystalline metals, which generally possess low rate sensitivity at room temperature. This technique has been validated herein, via self-consistency between rate jump and rate drop measurements, as a viable way to characterize rate dependent deformation behavior and thereby the underlying micromechanisms of plastic flow.

scholarly journals Superplastic Behavior of Al-Mg-Mn Alloy: An Experimental & Numerical Investigation

2018 ◽  
Vol 778 ◽  
pp. 45-52
Author(s):  
Tayyaba Zaman ◽  
Rehan Qayyume ◽  
Amjad Ali ◽  
Shaheed Khan ◽  
Chaoli Maa
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Deformation Mechanism ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Uniaxial Tensile ◽  
Sensitivity Index ◽  
Deformation Response ◽  
Surface Optical ◽  
Dominant Deformation Mechanism

Deformation response of Al-4.46Mg-0.48Mn alloy under uniaxial tensile loading was investigated at temperatures ranging from 400°C - 525°C and at strain rates of 3x10-3s-1, 1x 10-3s-1& 10-4s-1. The alloy exhibited a maximum elongation >480% at a strain rate of 10-3s-1and 525°C. At all conditions, the dominant deformation mechanism governing the superplastic deformation was investigated as a function of strain rate and temperature. The contributions of strain-rate sensitivity and strain hardening were analyzed in relation to the observed tensile ductility. The strain rate sensitivity index (m) and average activation energy (Q) values revealed that the dominant deformation mechanism is grain boundary sliding (GBS). The GBS phenomenon was further confirmed through high magnification examination of deformed surface. Optical microscopy (OM) and Scanning Electron Microscopy (SEM) showed that dynamic re-crystallization occurs during hot deformation of the alloy which causes reasonable enhancement of plasticity.

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