Corrigendum to “A simple dislocation model of deformation resistance of ultrafine-grained materials explaining Hall-Petch strengthening and enhanced strain rate sensitivity”

2011 ◽  
Vol 59 (15) ◽  
pp. 6205-6206 ◽  
Author(s):  
W. Blum ◽  
X.H. Zeng
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Deformation Resistance ◽  
Dislocation Model ◽  
Ultrafine Grained ◽  
Enhanced Strain ◽  
Ultrafine Grained Materials

The Effect of Grain Boundary Sliding and Strain Rate Sensitivity on the Ductility of Ultrafine-Grained Materials

2010 ◽  
Vol 667-669 ◽  
pp. 677-682 ◽  
Author(s):  
Nguyen Q. Chinh ◽  
Tamás Csanádi ◽  
Jenő Gubicza ◽  
Ruslan Valiev ◽  
Boris Straumal ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Room Temperature Ductility ◽  
Ultrafine Grained ◽  
Boundary Sliding ◽  
Ultrafine Grained Materials ◽  
High Strain Rate Sensitivity

Most ultrafine-grained (UFG) materials produced by severe plastic deformation (SPD) exibit only limited ductility which is correlated with the low strain rate sensitivity (SRS) of these materials. Recently, it was demonstrated that SPD is capable of increasing the room temperature ductility of aluminum-based alloys attaining elongations up to 150%, together with relatively high strain rate sensitivity. In the present work, additional results and discussions are presented on the effect of grain boundary sliding (GBS) and SRS on the ductility of some UFG metals and alloys. The characteristics of constitutive equations describing the steady-state deformation process are quantitatively analyzed for a better understanding of the effects of grain boundaries and strain rate sensitivity.

Strain-rate sensitivity of ultrafine-grained materials

2005 ◽  
Vol 96 (6) ◽  
pp. 566-571 ◽  
Author(s):  
H. W. Höppel ◽  
J. May ◽  
P. Eisenlohr ◽  
M. Göken
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Ultrafine Grained ◽  
Ultrafine Grained Materials

A Model of Enhanced Strain Rate Sensitivity in Nanocrystalline and Ultrafine-Grained Metals

2018 ◽  
Vol 57 (1) ◽  
pp. 1-10
Author(s):  
A.G. Sheinerman ◽  
S.V. Bobylev
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Activation Volume ◽  
Rate Sensitivity ◽  
Strong Increase ◽  
Anomalous Dependence ◽  
Ultrafine Grained ◽  
Enhanced Strain ◽  
Dislocation Pileups ◽  
Coble Creep

Abstract A model is suggested that describes enhanced strain rate sensitivity of nanocrystalline and ultrafine-grained metals. Within the model, plastic deformation of such metals incorporates dislocation transmission across grain boundaries (GBs) in the stress fields of dislocation pileups, the emission of individual dislocations from GBs as well as GB sliding accommodated by GB dislocation climb and/or Coble creep. The model predicts a strong increase in the strain rate sensitivity and a decrease in the activation volume with decreasing grain size, in accord with experimental data.We also considered the effect of GB sliding and Coble creep on the anomalous dependence of the activation volume on temperature observed in nanocrystalline Ni. It is demonstrated that although an account for GB sliding and Coble creep leads to the appearance of cusps in the temperature dependence of the activation volume, these mechanisms alone cannot be responsible for the observed anomalous dependence of the activation volume on temperature.

Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations

2006 ◽  
Vol 503-504 ◽  
pp. 31-36 ◽  
Author(s):  
Johannes Mueller ◽  
Karsten Durst ◽  
Dorothea Amberger ◽  
Matthias Göken
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Fcc Metals ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Indentation Strain

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.

Strain Rate Sensitivity of Ultrafine-Grained CP-Ti Processed by ECAP at Room Temperature

2010 ◽  
Vol 667-669 ◽  
pp. 707-712 ◽  
Author(s):  
Xiao Yan Liu ◽  
Xi Cheng Zhao ◽  
Xi Rong Yang
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Ultrafine Grained ◽  
Die Set ◽  
Increasing Temperature ◽  
Cp Ti

Ultrafine-grained (UFG) commercially pure (CP) Ti with a grain size of about 200 nm was produced by ECAP up to 8 passes using route BC at room temperature. For ECAP processing a proper die set was designed and constructed with an internal channel angle Φ of 120° and an outer arc of curvature Ψ of 20°. Strain rate sensitivity of UFG CP-Ti and CG CP-Ti were investigated by compression tests in the temperature range of 298~673K and strain rate range of 10-4~100s-1 using Gleeble simulator machine. Evolution of the microstructure during compression testing was observed using optical microscopy (OM) and transmission electron microscopy (TEM). Strain rate sensitivity value m of the UFG CP-Ti has been measured and is found to increase with increasing temperature and decreasing strain rate, and is enhanced compared to that of CG CP-Ti. Result of the deformation activation energy determination of UFG CP-Ti indicates that the deformation mechanism in UFG CP-Ti is correlated to the grain boundaries.

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