Grain size dependence of the activation parameters for plastic deformation: Influence of crystal structure, slip system, and rate-controlling dislocation mechanism

The correlation between the synthesis modes, chemical composition, crystal structure, surface microstructure, and also the mechanical properties of thin nanostructured Ni – Fe films has been studied. Thin Ni–Fe films on the Si with Au sublayer were obtained using electrolyte deposition with different current modes: direct current and three pulsed modes with pulse duration of 1 s, 10–3 and 10–5 s. It is shown that a decrease in the pulse duration to 10–5 s leads to an increase in the film elastic modulus and the hardness due to the small grain size and a large number of grain boundaries with increased resistance to plastic deformation. The effect of heat treatment at 100, 200, 300, and 400 °C on the surface microstructure and micromechanical properties of the films was investigated. An increase in grain size from 6 to 200 nm was found after heat treatment at 400 °C which, in combination with interfusion processes of the half-layer material, led to a significant decrease in hardness and elastic modulus. Ni–Fe films with improved mechanical properties can be used as coatings for microelectronic body for their electromagnetic protection.

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Grain-size dependence of plastic deformation in nanocrystalline Fe

Journal of Applied Physics ◽

10.1063/1.1569035 ◽

2003 ◽

Vol 93 (11) ◽

pp. 9282-9286 ◽

Cited By ~ 60

Author(s):

D. Jang ◽

M. Atzmon

Keyword(s):

Plastic Deformation ◽

Grain Size ◽

Size Dependence

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Pengaruh Pendopingan Karbon Terhadap Struktur Kristal dan Morfologi TIO2

Talenta Conference Series Science and Technology (ST) ◽

10.32734/st.v2i2.492 ◽

2019 ◽

Vol 2 (2) ◽

Author(s):

Frastica Deswardani ◽

Helga Dwi Fahyuan ◽

Rimawanto Gultom ◽

Eif Sparzinanda

Keyword(s):

Thin Film ◽

Crystal Structure ◽

Grain Size ◽

Tio2 Thin Film ◽

Crystal Size ◽

Diffraction Peak ◽

Carbon Doping ◽

Tio2 Anatase ◽

Spray Method ◽

Carbon Analysis

Telah dilakukan penelitian mengenai pengaruh konsentrasi doping karbon pada lapisan tipis TiO2 yang ditumbuhkan dengan metode spray terhadap struktur kristal dan morfologi TiO2. Hasil karakterisasi SEM menunjukkan bahwa penambahan doping karbon dapat meningkatkan ukuran butir. Lapisan TiO2 doping karbon 8% diperoleh ukuran butir terbesar adalah 1.35 μm, sedangkan ukuran tekecilnya adalah 0.45 μm. Sementara itu, untuk lapisan tipis TiO2 didoping karbon 15% memiliki ukuran butir terbesar yaitu 1.76 μm dan terkecil 0.9 μm. Hasil XRD menunjukkan seluruh puncak difraksi lapisan tipis TiO2 dengan doping karbon 8% dan 15% merupakan TiO2 anatase. Ukuran kristal lapisan TiO2 didoping karbon 8% diperoleh sebesar 638,08 Å dan untuk pendopingan 15% karbon ukuran kristal lapisan tipis TiO2 adalah 638,09 Å, hal ini menunjukkan ukuran kristal kedua sampel tidak mengalami perubahan yang signifikan. TiO2 thin film with carbon doping has been successfully grown by spray method. The research on the effect of carbon doping on crystal structure and morfology of TiO2 has been prepared by varying carbon concentration (8% and 15% carbon). Analysis of SEM showed that the addition of carbon may increase the grain size. Thin film of TiO2 doped carbon 8% has the largest grain size 1.35 μm, while the smallest grain size is 0.45 μm. Meanwhile, for thin film TiO2 doped carbon 15% has the largest grain size 1.76 μm and smallest 0.9 μm. The XRD results showed the entire diffraction peak of thin film TiO2 doped carbon 8% and 15% were TiO2 anatase. The crystal size of thin film TiO2 doped carbon 8% was obtained at 638.08 Å and for thin film TiO2 doped carbon 15% the crystalline size of TiO2 thin film was 638.09 Å, this shows that the crystal size of both samples did not change significantly.

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Structural Transformations and Mechanical Properties of Metastable Austenitic Steel under High Temperature Thermomechanical Treatment

Metals ◽

10.3390/met11040645 ◽

2021 ◽

Vol 11 (4) ◽

pp. 645

Author(s):

Igor Litovchenko ◽

Sergey Akkuzin ◽

Nadezhda Polekhina ◽

Kseniya Almaeva ◽

Evgeny Moskvichev

Keyword(s):

Plastic Deformation ◽

Grain Size ◽

High Temperature ◽

Austenitic Steel ◽

Structural Transformations ◽

Initial State ◽

Twin Boundaries ◽

Metastable Austenitic Steel ◽

Average Grain Size ◽

Heating Up

The effect of high-temperature thermomechanical treatment on the structural transformations and mechanical properties of metastable austenitic steel of the AISI 321 type is investigated. The features of the grain and defect microstructure of steel were studied by scanning electron microscopy with electron back-scatter diffraction (SEM EBSD) and transmission electron microscopy (TEM). It is shown that in the initial state after solution treatment the average grain size is 18 μm. A high (≈50%) fraction of twin boundaries (annealing twins) was found. In the course of hot (with heating up to 1100 °C) plastic deformation by rolling to moderate strain (e = 1.6, where e is true strain) the grain structure undergoes fragmentation, which gives rise to grain refining (the average grain size is 8 μm). Partial recovery and recrystallization also occur. The fraction of low-angle misorientation boundaries increases up to ≈46%, and that of twin boundaries decreases to ≈25%, compared to the initial state. The yield strength after this treatment reaches up to 477 MPa with elongation-to-failure of 26%. The combination of plastic deformation with heating up to 1100 °C (e = 0.8) and subsequent deformation with heating up to 600 °C (e = 0.7) reduces the average grain size to 1.4 μm and forms submicrocrystalline fragments. The fraction of low-angle misorientation boundaries is ≈60%, and that of twin boundaries is ≈3%. The structural states formed after this treatment provide an increase in the strength properties of steel (yield strength reaches up to 677 MPa) with ductility values of 12%. The mechanisms of plastic deformation and strengthening of metastable austenitic steel under the above high-temperature thermomechanical treatments are discussed.

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Finite element modelling of microstructural changes during equal channel angular drawing of pure aluminium

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06972-0 ◽

2021 ◽

Author(s):

Serafino Caruso ◽

Stano Imbrogno

Keyword(s):

Plastic Deformation ◽

Grain Size ◽

Finite Element ◽

Size Variation ◽

Fe Model ◽

Pure Aluminium ◽

Continuous Dynamic Recrystallization ◽

Research Activities ◽

Hardness Change ◽

Continuous Dynamic

AbstractGrain refinement by severe plastic deformation (SPD) techniques, as a mechanism to control microstructure (recrystallization, grain size changes,…) and mechanical properties (yield strength, ultimate tensile strength, strain, hardness variation…) of pure aluminium conductor wires, is a topic of great interest for both academic and industrial research activities. This paper presents an innovative finite element (FE) model able to describe the microstructural evolution and the continuous dynamic recrystallization (CDRX) that occur during equal channel angular drawing (ECAD) of commercial 1370 pure aluminium (99.7% Al). A user subroutine has been developed based on the continuum mechanical model and the Hall-Petch (H-P) equations to predict grain size variation and hardness change. The model is validated by comparison with the experimental results and a predictive analysis is conducted varying the channel die angles. The study provides an accurate prediction of both the thermo-mechanical and the microstructural phenomena that occur during the process characterized by large plastic deformation.

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Size-Dependence of Photoluminescence Property of ZnO Nanoparticles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.143 ◽

2014 ◽

Vol 887-888 ◽

pp. 143-146 ◽

Cited By ~ 2

Author(s):

Xiao Fang Wang ◽

Yun Liang Fang ◽

Tian Le Li ◽

Fu Juan Wang

Keyword(s):

Grain Size ◽

Lower Energy ◽

Size Dependence ◽

Surface States ◽

Photoluminescence Property ◽

Precipitation Method ◽

Pl Spectra ◽

Broadband Emission ◽

Band Emission ◽

20 Nm

Nanometer-sized ZnO crystals with the diameter from 20 nm to 110 nm were prepared by homogenous precipitation method (HPM). The photoluminescence (PL) spectra of as-prepared nanoparticles under excitation at the wavelength of 320 nm were detected. The PL spectra were fitted with Gaussian curves, in which a good fitting consisting of six Gaussian peaks was obtained. We observed that the multi-peak centers do not change much, while the relative amplitude of Gaussian combination to the band-to-band emission decreases rapidly with the increased grain size. It shows that the broadband emission at the lower energy is associated with the surface states.

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Computation on continuous grain refinement in AA1050 aluminum during repetitive tube expansion and shrinking technique

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420715625086 ◽

2015 ◽

Vol 232 (4) ◽

pp. 307-318

Author(s):

H Jafarzadeh ◽

K Abrinia

Keyword(s):

Finite Element Method ◽

Plastic Deformation ◽

Grain Size ◽

Finite Element ◽

Dislocation Density ◽

Severe Plastic Deformation ◽

Grain Refinement ◽

Half Cycle ◽

Tube Expansion ◽

Element Method

The microstructure evolution during recently developed severe plastic deformation method named repetitive tube expansion and shrinking of commercially pure AA1050 aluminum tubes has been studied in this paper. The behavior of the material under repetitive tube expansion and shrinking including grain size and dislocation density was simulated using the finite element method. The continuous dynamic recrystallization of AA1050 during severe plastic deformation was considered as the main grain refinement mechanism in micromechanical constitutive model. Also, the flow stress of material in macroscopic scale is related to microstructure quantities. This is in contrast to the previous approaches in finite element method simulations of severe plastic deformation methods where the microstructure parameters such as grain size were not considered at all. The grain size and dislocation density data were obtained during the simulation of the first and second half-cycles of repetitive tube expansion and shrinking, and good agreement with experimental data was observed. The finite element method simulated grain refinement behavior is consistent with the experimentally obtained results, where the rapid decrease of the grain size occurred during the first half-cycle and slowed down from the second half-cycle onwards. Calculations indicated a uniform distribution of grain size and dislocation density along the tube length but a non-uniform distribution along the tube thickness. The distribution characteristics of grain size, dislocation density, hardness, and effective plastic strain were consistent with each other.

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The grain size dependence of flow stress in a Cu–26Ni–17Zn alloy

Acta Materialia ◽

10.1016/s1359-6454(99)00464-4 ◽

2000 ◽

Vol 48 (8) ◽

pp. 1807-1813 ◽

Cited By ~ 19

Author(s):

S. Nagarjuna ◽

M. Srinivas ◽

K.K. Sharma

Keyword(s):

Grain Size ◽

Flow Stress ◽

Size Dependence

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