A Recrystallisation Based Investigation for Efficiency of Processing Routes during Equal Channel Angular Extrusion

2004 ◽  
Vol 467-470 ◽  
pp. 1325-1332 ◽  
Author(s):  
Satyam Suwas ◽  
André Eberhardt ◽  
László S. Tóth ◽  
Jean-Jacques Fundenberger ◽  
Thierry Grosdidier
Keyword(s):  
Differential Scanning Calorimetry ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Cold Work ◽  
Stacking Fault ◽  
Stored Energy ◽  
Scanning Calorimetry ◽  
Angular Extrusion ◽  
Refinement Process ◽  
Stacking Fault Energies

The amount of stored energy of cold work for the processing routes A and Bc of Equal Channel Angular Extrusion (ECAE) process has been measured using differential scanning calorimetry. The study is preceded by the effect of amount of ECAE deformation on materials of different stacking fault energies, namely Cu and Ag. The results indicate that the different processing routes have significant effect on the stored energy, which is likely to affect the grain refinement process.

Grain Refinement and Texture Evolution during Equal Channel Angular Extrusion of Pure Cu and Cu-Zn Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 1215-1218
Author(s):  
Hai Hong Chen ◽  
Sai Yi Li ◽  
Dong Hong Zhang ◽  
Xin Huang
Keyword(s):  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Texture Evolution ◽  
Shear Bands ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Zn Content ◽  
Angular Extrusion ◽  
Pure Cu ◽  
Stacking Fault Energies

Equal channel angular extrusion (ECAE) experiments were conducted on as-cast pure Cu, Cu–10%Zn, and Cu–30%Zn, using a 90 die for up to 4 passes. The stacking fault energies (SFEs) of the three materials decrease with increasing Zn content. The microstructures and textures of the processed billets were analyzed using optical microscope and X-ray diffraction, respectively. The results show that the structures of the three materials were all significantly refined after ECAE and a lower SFE led to a finer microstructure with a higher density of shear bands. The textures were considerably weakened after 4 passes, more apparent in the material with a lower SFE. It is concluded that the SFE has significant influences on both the grain refinement and texture evolution during ECAE deformation.

Influence of Stacking Fault Energy on the Microstructures and Grain Refinement in the Cu-Al Alloys during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 379-384 ◽  
Author(s):  
X.H. An ◽  
Shi Ding Wu ◽  
Z.F. Zhang
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Al Alloys ◽  
Stacking Fault ◽  
High Recovery ◽  
Angular Pressing ◽  
High Recovery Rate ◽  
Refinement Mechanism ◽  
Stacking Fault Energies

The microstructural evolution and grain refinement of Cu-Al alloys with different stacking fault energies (SFEs) processed by equal-channel angular pressing (ECAP) were investigated. The grain refinement mechanism was gradually transformed from dislocation subdivision to twin fragmentation with tailoring the SFE of Cu-Al alloys. Concurrent with the transition of grain refinement mechanism, the grain size can be refined into from ultrafine region (1 m~100 nm) to the nanoscale (<100 nm) and then it is found that the minimum equilibrium grain size decreases in a roughly linear way with lowering the SFE. Moreover, in combination with the previous results, it is proposed that the formation of a uniform ultrafine microstructure can be formed more readily in the materials with high SFE due to their high recovery rate of dislocations and in the materials with low SFE due to the easy formation of a homogeneously-twinned microstructure.

scholarly journals Differential Scanning Calorimetry of Metamict Pu-Substituted Zirconolite

1982 ◽  
Vol 15 ◽  
Author(s):  
Dean E. Peterson ◽  
Frank W. Clinard
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Ambient Temperature ◽  
Total Energy ◽  
Temperature Dependence ◽  
Radiation Damage ◽  
Rate Constant ◽  
Stored Energy ◽  
Scanning Calorimetry ◽  
No Release

ABSTRACTSamples of CaPuTi2O7 were prepared by cold pressing and sintering. Plutonium was substituted for zirconium in order to characterize radiation damage effects. The energy stored in a sample which had reached saturation in swelling after storage at ambient temperature was measured with a differential scanning calorimeter. The total energy of 6.6±0.1 cal/g is released over the range 485–715° C. The activation energy of annealing of the damage is 1.22±0.05 eV. The temperature dependence of the rate constant is described by kT= 5.96E4 exp(−1.22/kBT) s−1 where kB and T are the Boltzmann's constant and temperature(K) respectively. A sample stored at 600°C was similarly evaluated and showed no release of stored energy to the precision of the apparatus (±0.1 cal/g). These results are applied to analysis of waste incorporation in Synroc and are correlated with analogous parameters for other materials.

Equal channel angular pressing processing routes and associated structure modification: a differential scanning calorimetry and X-ray line profile analysis

2012 ◽  
Vol 27 (3) ◽  
pp. 194-199 ◽  
Author(s):  
A. Sarkar ◽  
Satyam Suwas ◽  
D. Goran ◽  
J.-J. Fundenberger ◽  
L.S. Toth ◽  
...  
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Equal Channel Angular Pressing ◽  
Line Profile ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Stored Energy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Angular Pressing

The effectiveness of different routes of equal channel angular pressing (A, Bc, and C) is studied for commercially pure copper. The stored energy and the activation energy of recrystallization for the deformed samples were quantified using differential scanning calorimetry and X-ray diffraction line profile analysis. Results of the study revealed that the dislocation density and the stored energy are higher in the case of route Bc deformed sample. The activation energy for recrystallization is lower for route Bc.

Equal Channel Angular Extrusion (ECAE) of Ni-Ti Based Shape Memory Alloy Systems

2007 ◽  
Vol 539-543 ◽  
pp. 3195-3200
Author(s):  
Chin Jye Yu ◽  
Chiang Shu Lei ◽  
Rabindra Mahapatra ◽  
Jeff Sharp ◽  
Ibrahim Karaman
Keyword(s):  
Shape Memory ◽  
Equal Channel Angular Extrusion ◽  
Temperature Hysteresis ◽  
Scanning Calorimetry ◽  
Microstructural Refinement ◽  
Transformation Temperatures ◽  
Shape Memory Behavior ◽  
Transmission Electron ◽  
Angular Extrusion ◽  
Substructure Formation

In this paper we report the effects of Equal Channel Angular Extrusion (ECAE) processing on the phase transformation characteristics of Ni-Ti based shape memory alloys in terms of transformation temperatures, temperature hysteresis, and microstructural evolution. The ECAE process affects the material’s shape memory behavior via microstructural refinement. Differential Scanning Calorimetry (DSC) and Transmission Electron Microscopy (TEM) were utilized to investigate the effects of microtructural refinement and substructure formation on the shape memory behavior of these alloys. The microstructural refinement was found to have significant influence on the transformation temperatures.

Microstructure and Wear Properties of GCr15 Alloy Produced by Equal Channel Angular Extrusion

2011 ◽  
Vol 211-212 ◽  
pp. 661-665
Author(s):  
Guo Quan Xiang ◽  
Min Xin Zheng ◽  
Lian Qing Ji
Keyword(s):  
Grain Size ◽  
Mass Loss ◽  
Grain Refinement ◽  
Equal Channel Angular Extrusion ◽  
Optical Microscope ◽  
Wear Properties ◽  
Gcr15 Steel ◽  
Angular Extrusion

GCr15 alloy produced by hot-forged is subjected to equal channel angular extrusion (ECAE) process at 950°C. The microstructure of GCr15 steel via ECAE and annealed is studied by an optical microscope. The effect of ECAE and annealing on the wear properties of the alloy is also investigated. The results show that the grain size reduced from 50 mm to 10 mm via one pass ECAE, and the hardness of the alloy is increased. The wear mass loss of the alloy is greatly reduced due to the grain-refinement after ECAE and annealing.

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