Discussion of strong pinning effect via nonuniform PSSW mode in Fe/NiFe/Fe multi-layer films with different Fe film thicknesses

2020 ◽  
Vol 500 ◽  
pp. 166399 ◽  
Author(s):  
Yu Liu ◽  
Zhongwen Lan ◽  
Zhong Yu ◽  
Rongdi Guo ◽  
Xiaona Jiang ◽  
...  
Keyword(s):  
Pinning Effect ◽  
Strong Pinning

Static Recrystallization in Aluminum/Graphene Composites

2021 ◽  
Vol 1016 ◽  
pp. 1636-1641
Author(s):  
Xiao Dong Wu ◽  
Xiao Li Liu ◽  
Ling Fei Cao ◽  
Guang Jie Huang
Keyword(s):  
Annealing Temperature ◽  
Static Recrystallization ◽  
Recrystallization Behavior ◽  
High Annealing Temperature ◽  
Graphene Composite ◽  
Pinning Effect ◽  
High Annealing ◽  
Rolled Aluminum ◽  
Strong Pinning ◽  
Cold Rolled

The aim of this work was to analyze the recrystallization behavior of cold rolled Aluminum/graphene composites during annealing. The Aluminum/graphene composite was cold rolled firstly, and then annealed at different temperature (250°C, 300°C, 350°C, 400°C) and for various time (1 h, 2 h, 8 h, 32 h). Full recrystallization did not occur until the annealing temperature was above 300 °C. With annealing temperature increasing from 250 to 300°C, the hardness of the composites decreased from 49.6 to 27.6 HV. Grain growth were not observed at high annealing temperature and longer annealing time, which suggested that Graphene has strong pinning effect on the grain boundary of Aluminum.

Strong pinning effect of alumina/nanodiamond composites obtained by pulsed electric current sintering

2013 ◽  
Vol 33 (10) ◽  
pp. 2043-2048 ◽  
Author(s):  
J.S. Moya ◽  
R. Torrecillas ◽  
L.A. Díaz ◽  
T. Rodriguez-Suarez ◽  
L. Goyos ◽  
...  
Keyword(s):  
Electric Current ◽  
Pinning Effect ◽  
Pulsed Electric Current ◽  
Strong Pinning

Effects of Mn and Cr Additions on the Recrystallization Behavior of Al-Mg-Si-Cu Alloys

2016 ◽  
Vol 877 ◽  
pp. 172-179
Author(s):  
Gong Wang Zhang ◽  
Hiromi Nagaumi ◽  
Yi Han ◽  
Yi Xu ◽  
Chad M. Parish ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hot Deformation ◽  
Hydraulic Press ◽  
Recrystallization Behavior ◽  
Number Density ◽  
Pinning Effect ◽  
Cu Alloys ◽  
Strong Pinning ◽  
Ebsd Technique ◽  
Temperature Exposure

Upsetting tests on two newly developed Mn and Cr-containing Al-Mg-Si-Cu alloys with various Mn contents were carried out at a speed of 15 mm/s under upsetting temperature of 450 °C after casting and subsequent homogenization heat treatment using a 300-Tone hydraulic press. STEM experiments revealed that Mn and Cr-containing α-Al (MnCrFe)Si dispersoids formed during homogenization showed a strong pinning effect on dislocations and grain boundaries, which could effectively inhibit recovery and recrystallization during hot deformation in the two alloys. Recrystallization fractions after solution heat treatment following hot deformation were measured by EBSD technique. It was found that the recrystallization fractions of the two alloys were less than 30%, giving rise to lower recrystallization fraction in the alloy with higher amount of Mn, which had higher number density of dispersoids. This implied that the finely distributed α-dispersoids were rather stable against coarsening and they stabilized the microstructure by inhibiting dislocation recovery and recrystallization during elevated temperature exposure. Increasing the content of Mn could increase the number density as well as the aspect ratio of the dispersoids, and more significantly, the effect of retardation on recrystallization were further enhanced.

scholarly journals Investigation on Microstructural Evolution and Properties of an Al-Cu-Li Alloy with Mg and Zn Microalloying during Homogenization

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1010 ◽  
Author(s):  
Hongying Li ◽  
Weichen Yu ◽  
Xiaoyu Wang ◽  
Rong Du ◽  
Wen You
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Yield Strength ◽  
Microstructural Evolution ◽  
Cast Alloy ◽  
Second Step ◽  
Pinning Effect ◽  
Atom Clusters ◽  
Deformation Ability ◽  
Strong Pinning

The microstructural evolution and properties of an Al-Cu-Li alloy with Mg and Zn microalloying (Al-3.5Cu-1.5Li-0.5Mg-0.4Zn-0.3Mn-0.12Zr-0.06Ti) ingot subjected to homogenization (second-step annealing at 500 °C for 24 h following first-step annealing at 400 °C for 8 h) were investigated. Mg-Zn atom clusters were enriched at the end of dendrites as well as low-melting eutectic phases such as S (Al2CuMg), T2 (Al6CuLi3), TB (Al7.5Cu4Li) and T1 (Al2CuLi) in the as-cast alloy. During homogenization, Mg-Zn atom clusters diffused from the segregation to the vacancies, leading to the dissolution of the low-melting eutectic phases. Not only Al3Zr particles were observed at 500 °C, but more fine and uniform spherical dispersoids appeared, which were assumed as Al3(ZrxTiyLi1−x−y). Mg and Zn microalloying can promoted the nucleation of Al3Zr and Al3(ZrxTiyLi1−x−y) dispersoids, as well as T (Al20Cu2Mn3) phases, which all inhibited recrystallization effectively and improve the uniformity of the grains due to the strong pinning effect. The yield ratio was decreased from 0.81 to 0.52 with the yield strength decreased from 172 MPa to 61 MPa, which showed better plastic deformation ability of the alloy subjected to homogenization. In addition, the dissolution of low-melting eutectic phases and formation of Al3(ZrxTiyLi1−x−y) dispersoids resulted in the significant improvement on thermal stability.

Phase Field Modeling of Recrystallization Grain Growth during Re-Aging Process in Cu-Ni-Si Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 1805-1808
Author(s):  
Yong Qiang Long ◽  
Ping Liu ◽  
Wei Min Zhang
Keyword(s):  
Grain Growth ◽  
Phase Field ◽  
Aging Process ◽  
Structural Evolution ◽  
Diffuse Interface ◽  
Gradual Transition ◽  
Ginzburg Landau ◽  
Pinning Effect ◽  
Structural Variables ◽  
Strong Pinning

The micro structural evolution and the mechanism of recrystallization grain growth were studied during re-aging process in Cu-Ni-Si alloy containing finely pre-aging δ-Ni2Si precipitates using computer simulations based on a diffuse-interface phase-field kinetic model. In this model, the temporal evolution of the spatially dependent field variables is determined by numerically solving the time-dependent Ginzburg-Landau (TDGL) equations for the structural variables. The simulation results quantify the effects of the precipitation on recrystallization. It is shown that the finely dispersed pre-aging δ-Ni2Si precipitates exert a strong pinning effect on the recrystallization grain boundaries. The recrystallization grain growth for r = 3 fa = 0.015 can be described as R =1.04∗t 0.33 at the beginning, followed by a gradual transition to growth stagnation. The final grain size follows a Zener type relation lim 0.49 1.41 a R r f =     for 0.01 ≤ fa ≤ 0.21 and r = 2.5 or 3.

Oxygen adsorption and VDR effect in (Sr, Ca)TiO3−x based ceramics

1990 ◽  
Vol 5 (12) ◽  
pp. 2910-2922 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Noboru Ichinose
Keyword(s):  
High Temperature ◽  
Voltage Dependence ◽  
Energy Levels ◽  
Oxygen Adsorption ◽  
Oxygen Chemisorption ◽  
Pinning Effect ◽  
Chemisorbed Oxygen ◽  
Strong Pinning ◽  
Current Characteristics ◽  
Trap Levels

The relation between the oxygen adsorption and the voltage dependence of the resistor (VDR effect) in (Sr, Ca)TiO3−x based ceramics has been investigated. The nonlinearity of the voltage-current characteristics increased with increasing the barrier height, which is thought to be generated by the oxygen chemisorption. Acceptor type trap levels were detected by means of a zero biased DLTS technique at high temperatures. These interfacial energy levels changed with reoxidizing temperatures, and the change can be explained by the degradation of the chernisorbed oxygen. The high temperature type of the chemisorbed oxygen as O2− and O is relatively stable due to the strong pinning effect of trapped electrons, with reoxidizing anneals of grain surfaces above the oxidation temperature, and it contributes greatly to the VDR effect. It is concluded that energy barriers are caused by the interface states generated by the chemisorbed oxygen on grain surfaces and that they determine the VDR effect.

scholarly journals Interdependent Linear Complexion Structure and Dislocation Mechanics in Fe-Ni

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1128
Author(s):  
Vladyslav Turlo ◽  
Timothy J. Rupert
Keyword(s):  
Large Scale ◽  
Strain Curve ◽  
Dislocation Motion ◽  
Atomistic Simulations ◽  
Aging Behavior ◽  
Stress Strain Curve ◽  
Pinning Effect ◽  
Dislocation Mechanics ◽  
Ni Alloy ◽  
Strong Pinning

Using large-scale atomistic simulations, dislocation mechanics in the presence of linear complexions are investigated in an Fe-Ni alloy, where the complexions appear as nanoparticle arrays along edge dislocation lines. When mechanical shear stress is applied to drive dislocation motion, a strong pinning effect is observed where the defects are restricted by their own linear complexion structures. This pinning effect becomes weaker after the first dislocation break-away event, leading to a stress-strain curve with a profound initial yield point, similar to the static strain aging behavior observed experimentally for Fe-Mn alloys with the same type of linear complexions. The existence of such a response can be explained by local diffusion-less and lattice distortive transformations corresponding to L10-to-B2 phase transitions within the linear complexion nanoparticles. As such, an interdependence between a linear complexion structure and dislocation mechanics is found.

Electronic States and Doping Effect of Carbon in the Kink of BCC Iron

2009 ◽  
Vol 293 ◽  
pp. 1-9
Author(s):  
Zheng Chen Qiu ◽  
Can Fang Xia ◽  
Li Qun Chen
Keyword(s):  
Electronic Structure ◽  
Edge Dislocation ◽  
First Principles ◽  
Density Functional ◽  
Electronic States ◽  
Functional Theory ◽  
Pinning Effect ◽  
Bcc Iron ◽  
Strong Pinning ◽  
Solute Hardening

By the use of the first-principles method, based upon density functional theory, we investigated the effect of C upon the electronic structure of a kink on the ½[111](1¯10) edge dislocation in bcc iron. The results show that C has a tendency to segregate towards the kink. The structural energies of some atoms of interest in the kink with C are lower than those of corresponding atoms in the clean kink. Furthermore, the interactions between C and the neighboring Fe atoms are very strong due to the hybridization between the C 2p state and the Fe 3d4s4p states. We find that there exists some charge accumulations between C and the neighboring Fe atoms. The analysis of the electronic structure indicates that the introduction of C can stabilize the kink system and impede the sideways motion of the kink. The C induces a strong pinning effect on the ½[111](1¯10) edge dislocation and may result in solid solute hardening.

Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 92-93
Author(s):  
H. Watanabe ◽  
B. Kabius ◽  
B. Roas ◽  
K. Urban
Keyword(s):  
Defect Formation ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Structural Disorder ◽  
Flux Lines ◽  
Pinning Effect ◽  
Magnetic Flux Lines ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

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