Crystal Plasticity (Volume III)

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Metals and Alloys".

Deadline for manuscript submissions: closed (31 October 2023) | Viewed by 25709

Special Issue Editor

Department of Design and Engineering, Bournemouth University, Poole BH12 5BB, UK
Interests: severe plastic deformation; superplasticity; ultrafine-grained materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Due to the first and second volumes of the Special Issue "Crystal Plasticity" being highly successful, with the topic seemingly being very attractive for the manufacturing industry and materials scientists, it is my pleasure to announce the Special Issue "Crystal Plasticity Volume III".

A variety of complex application environments drive the demand for the development of high-performance engineering materials, including material strength, deformation resistance, light-weighting, corrosion resistance, high-temperature capability, material processing efficiency, sustainability and multifunctionality. The progress in the development of high-performance materials can be achieved either by developing and applying novel methods of investigation or by preparing materials with novel structural features and/or properties. In this Special Issue, potential papers could include all aspects of processing, structure/property evaluation and applications of both ferrous and nonferrous materials, composites (including biomaterials, high-temperature materials, and nanomaterials for energy and structural applications), structural metallic materials, ultrafine-grained materials, high-entropy alloys and nuclear materials. Potential papers can include, but are not limited to, the following subjects, covering the processing of high-performance engineering materials:

  • Materials processing;
  • Material strengthening mechanism;
  • Phase transformations and microstructure control;
  • Crystallographic texture evolution;
  • Microstructure characterisations.

Dr. Yi Huang
Guest Editor

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Keywords

  • plasticity
  • thermomechanical processing
  • severe plastic deformation
  • metals and alloys
  • intermetallics
  • relationship between microstructure and mechanical property

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Related Special Issues

Published Papers (14 papers)

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Research

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12 pages, 9336 KiB  
Article
Indentation Size Effect in Electrodeposited Nickel with Different Grain Size and Crystal Orientation
by Petr Haušild, Jaroslav Čech, Miroslav Karlík, Marc Legros, Jiří Nohava and Benoit Merle
Crystals 2023, 13(9), 1385; https://doi.org/10.3390/cryst13091385 - 18 Sep 2023
Viewed by 1160
Abstract
Indentation size effect at shallow indentation depths still remains a challenge as it cannot be correctly described by the Nix–Gao model based on the concept of strain gradient plasticity and geometrically necessary dislocations. The reasons for this discrepancy may be various, and multiple [...] Read more.
Indentation size effect at shallow indentation depths still remains a challenge as it cannot be correctly described by the Nix–Gao model based on the concept of strain gradient plasticity and geometrically necessary dislocations. The reasons for this discrepancy may be various, and multiple microstructural factors may play a role at the nanoscale. In the present paper, the breakdown of the Nix–Gao model was explored in electrodeposited nickel with different grain size/shape and crystallographic orientation. Crystallographic orientation has no significant effect on the indentation process at shallow depths if plastic deformation has already developed. On the other hand, decreasing the grain size leads to constrained plastic deformation in the grains below the indenter and to an effective plastic zone expansion. Further grain refinement down to the nanograin material leads to a change in the plastic deformation mechanisms to grain boundary-mediated deformation and a more pronounced breakdown of the Nix–Gao model. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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69 pages, 20668 KiB  
Article
Characteristics of Wires of the Long-Operated Aluminum-Steel Cable at Different Places on an Overhead Power Line Span
by Aleksandr A. Levin, Andrei G. Panfilov, Alexey I. Lihachev, Maria V. Narykova, Boris K. Kardashev, Andrej G. Kadomtsev, Nikita D. Prasolov, Roman V. Sokolov, Pavel N. Brunkov, Makhsud M. Sultanov, Victor G. Kul’kov, Ilia A. Boldyrev and Dzhonibek Sh. Norov
Crystals 2023, 13(8), 1253; https://doi.org/10.3390/cryst13081253 - 14 Aug 2023
Viewed by 1251
Abstract
During operation, cables of overhead power lines (OPLs) are exposed to the impact that differs in separate parts of the OPL span due to the different responses of cables near the clamps and far from them. This paper presents the results of a [...] Read more.
During operation, cables of overhead power lines (OPLs) are exposed to the impact that differs in separate parts of the OPL span due to the different responses of cables near the clamps and far from them. This paper presents the results of a study of aluminum and steel wires cut from such separate parts of ACSR cables before and after exploitation. Structural, microstructural, and elastic–microplastic properties of wires and their changes during operation were studied through optical microscopy, energy-dispersive X-ray microanalysis, electron backscattering diffraction, X-ray diffraction, densitometry, and acoustic measurements. The characteristics of the properties of the wires along the span were found to change in a coordinated manner. Numerical estimates of the influence of the steel core on aging the ACSR cable were obtained. Changes in the properties of the wires, as well as oxidization and corrosion of their near-surface layers, were studied in detail. Quantitative values of the characteristics of properties, the most distant from those observed in the new wires, were revealed for samples of aluminum and steel wires cut from the cable at 1/4 span and near clamps. It is assumed that these cable parts should be the most crucial for cable durability. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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12 pages, 3954 KiB  
Article
Microstructures, Mechanical Properties and Transformation Behavior in Ni49.6Ti35.4Hf15 Alloy Produced with High-Pressure Torsion
by Jintao Zhang, Shibo Wang, Hua Ding, Peng Hu, Yi Huang and Yu Zhang
Crystals 2023, 13(8), 1246; https://doi.org/10.3390/cryst13081246 - 12 Aug 2023
Cited by 2 | Viewed by 1243 | Correction
Abstract
High-pressure torsion (HPT) was applied for the Ni49.6Ti35.4Hf15 (at.%) alloy up to 1/4, 2 and 16 turns under a pressure of 4.0 GPa. The samples were examined using X-ray diffraction (XRD), transmission electron microscope (TEM) and microhardness measurements. [...] Read more.
High-pressure torsion (HPT) was applied for the Ni49.6Ti35.4Hf15 (at.%) alloy up to 1/4, 2 and 16 turns under a pressure of 4.0 GPa. The samples were examined using X-ray diffraction (XRD), transmission electron microscope (TEM) and microhardness measurements. The results indicate that the mixture of an amorphous and nanocrystalline microstructure developed in the investigated NiTiHf alloy as the number of HPT turns was increased to two. The average hardness of the samples increased from 330 Hv to 500 Hv after 16 turns of HPT. Very fine martensite developed when the HPT-processed samples were annealed at 550 °C and the finer microstructures were attained with higher HPT turns. Differential scanning calorimetry (DSC) tests were performed in the post-HPT annealing samples to clarify the transformation behavior after severe plastic deformation in HPT and subsequent annealing, so as to provide an experimental basis for the application of the shape memory alloy. The transformation temperature of the alloy decreased remarkably when the number of turns of HPT reached 16. It is suggested that the deformation extent and annealing temperatures should be considered in order to maintain a high transformation temperature while utilizing the strengthening effect of HPT in the NiTiHf alloy. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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15 pages, 7042 KiB  
Article
Development of the Forming Limit Diagram for AA6016-T4 at Room Temperature Using Uniaxial Tension of Notched Samples and a Biaxial Test
by Ahmed Elsayed, Diego Gonzalez and Evgenia Yakushina
Crystals 2023, 13(7), 1134; https://doi.org/10.3390/cryst13071134 - 20 Jul 2023
Viewed by 2107
Abstract
Within the framework of the formability limit assessment in sheet metal forming, testing of notched tensile samples coupled with digital image correlation (DIC) has been analysed as an alternative to overcome the implications of Nakajima testing in relation to times of test preparation, [...] Read more.
Within the framework of the formability limit assessment in sheet metal forming, testing of notched tensile samples coupled with digital image correlation (DIC) has been analysed as an alternative to overcome the implications of Nakajima testing in relation to times of test preparation, cost of the equipment, presence of friction, and amount of material required for the test. Additionally, the complications of the Nakajima testing at elevated temperatures need to also be considered. In this work, specific notched sample geometries have been investigated to accurately identify the forming limits of Aluminium alloy AA6016 in T4 condition. Once the notched geometry had been defined, experimental tensile testing of the samples coupled with DIC technology allowed us to identify the formability limits of interest. Finally, a comparison at room temperature with the conventional Nakajima testing was performed experimentally. Two different methodologies for strain limit evaluation in notched samples have been investigated in the present analysis. The first one is called a position-dependent method and is based on the inverse best-fit parabola of the “bell-shaped curve”, which is used in the conventional Nakajima test. The second approach referred to a time-dependent method and is based on the strain rate evaluation at the necking zone. This strain-rate-dependent method, which works in combination with DIC measurements, was found to be more accurate to determine the necking limits than the previous one; in addition, it also provides more accurate information for the safe zone of forming. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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21 pages, 14446 KiB  
Article
Simulation of the Cyclic Stress–Strain Behavior of the Magnesium Alloy AZ31B-F under Multiaxial Loading
by Vitor Anes, Rogério Moreira, Luís Reis and Manuel Freitas
Crystals 2023, 13(6), 969; https://doi.org/10.3390/cryst13060969 - 19 Jun 2023
Cited by 3 | Viewed by 1363
Abstract
Under strain control tests and cyclic loading, extruded magnesium alloys exhibit a special mechanism of plastic deformation (“twinning” and “de-twining”). As a result, magnesium alloys exhibit an asymmetric material behavior that cannot be fully characterized with the typical numerical tools used for steels [...] Read more.
Under strain control tests and cyclic loading, extruded magnesium alloys exhibit a special mechanism of plastic deformation (“twinning” and “de-twining”). As a result, magnesium alloys exhibit an asymmetric material behavior that cannot be fully characterized with the typical numerical tools used for steels or aluminum alloys. In this sense, a new phenomenological model, called hypo-strain, has been developed to correctly predict the cyclic stress–strain evolution of magnesium alloys. On this basis, this work aims to accurately describe the local cyclic elastic–plastic behavior of AZ31B-F magnesium alloy under multiaxial cyclic loading with Abaqus incremental plasticity. The phenomenological hypo-strain model was implemented in the UMAT subroutine of Abaqus/Standard to be used as a design tool for mechanical design. To evaluate this phenomenological approach, the results were correlated with the uniaxial and multiaxial proportional and non-proportional experimental tests. In addition, the estimates were also correlated with the Armstrong–Frederick nonlinear kinematic hardening model. The results show a good correlation between the experiments and the phenomenological hypo strain approach. The model and its implementation were validated in the strain range studied. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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14 pages, 3587 KiB  
Article
Consolidation of Zn-Hydroxyapatite and Zn-Bioactive Glass Composites Using High-Pressure Torsion
by Amanda P. Carvalho, Andressa C. de O. Assunção, Jorgimara de O. Braga, Débora R. Lopes, Diogo M. M. dos Santos, Eduardo Henrique M. Nunes, Fernando Cotting and Roberto B. Figueiredo
Crystals 2023, 13(6), 949; https://doi.org/10.3390/cryst13060949 - 13 Jun 2023
Cited by 1 | Viewed by 1137
Abstract
There has been a great interest in developing zinc-based composites for biological applications. Mixing bioactive particles and obtaining a well-dispersed structure is not straight forward though. The present study reports a novel processing route in which zinc particles are mixed with hydroxyapatite and [...] Read more.
There has been a great interest in developing zinc-based composites for biological applications. Mixing bioactive particles and obtaining a well-dispersed structure is not straight forward though. The present study reports a novel processing route in which zinc particles are mixed with hydroxyapatite and bioactive glass particles and consolidated at room temperature using high-pressure torsion. The composites display good dispersion of second phase particles, enhanced strength and an increased corrosion rate in the Hank’s balanced salt solution. The incorporation of these particles can be used to tailor the corrosion rate of zinc. It is shown that the surface layer of the corrosion product in the zinc-bioactive particle composites is richer in calcium and phosphorous than the pure zinc counterpart. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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15 pages, 7471 KiB  
Article
Microhardness and Microstructural Evolution of Pure Nickel Processed by High-Pressure Torsion
by Meng Sun, Chaogang Ding, Jie Xu, Debin Shan, Bin Guo and Terence G. Langdon
Crystals 2023, 13(6), 887; https://doi.org/10.3390/cryst13060887 - 28 May 2023
Cited by 2 | Viewed by 1793
Abstract
High-purity Ni was processed by high-pressure torsion (HPT) at room temperature under an imposed pressure of 6.0 GPa and a rotation rate of 1 rpm through 1/4 to 10 turns, and samples were then examined using Electron Back-Scattered Diffraction (EBSD) and microhardness measurements. [...] Read more.
High-purity Ni was processed by high-pressure torsion (HPT) at room temperature under an imposed pressure of 6.0 GPa and a rotation rate of 1 rpm through 1/4 to 10 turns, and samples were then examined using Electron Back-Scattered Diffraction (EBSD) and microhardness measurements. The results show that the grain size and low-angle grain boundaries (LAGBs) gradually decrease with the growth of HPT revolutions while the microhardness values gradually increase. After 10 turns of HPT processing, ultrafine-grained (UFG) pure Ni with a reasonable microhardness value and microstructure homogeneity can be achieved across the disk, thereby giving great potential for applications in micro-forming. A grain refinement model for severe plastic deformation (SPD) of pure Ni is proposed. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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12 pages, 6304 KiB  
Article
Shape Memory Properties and Microstructure of FeNiCoAlTaB Shape Memory Alloys
by Li-Wei Tseng, Po-Yu Lee, Nian-Hu Lu, Yi-Ting Hsu and Chih-Hsuan Chen
Crystals 2023, 13(5), 852; https://doi.org/10.3390/cryst13050852 - 22 May 2023
Cited by 2 | Viewed by 1521
Abstract
The three-point-bending shape memory properties, microstructure, and magnetic properties of Fe40.95Ni28Co17Al11.5Ta2.5B0.05 (at.%) alloys were investigated. The magnetic results showed a martensitic transformation in the samples that were aged at 700 °C for [...] Read more.
The three-point-bending shape memory properties, microstructure, and magnetic properties of Fe40.95Ni28Co17Al11.5Ta2.5B0.05 (at.%) alloys were investigated. The magnetic results showed a martensitic transformation in the samples that were aged at 700 °C for 6 and 12 h under the applied magnetic fields of 0.05 and 7 Tesla. The martensitic start temperature increased from −113 °C to −97 °C as aging times increased from 6 to 12 h. Increasing the magnetic fields from 0.05 to 7 Tesla, the transformation temperatures increased to a higher temperature. Both samples reach saturation magnetization (140 emu/g) under 7 Tesla. The 98.5% cold-rolled alloys that were annealed at 1250 °C for 0.5 h presented a strong <100> texture in the rolling direction with an average grain size of 360 μm. Increasing the annealing time to 1 h, the intensity of texture reduced from 31.61 to 23.19. The fraction of low angle grain boundaries (LABs) for the 98.5% CR samples after annealing at 1250 °C for 0.5 h and 1 h was about 24.6% and 16.1%, respectively. Three-point-bending results show that the sample aged at 700 °C for 6 h displayed 0.2% recoverable strain at a stress level of 800 MPa. Failure occurred before the 900 MPa cycle could be completed. The sample aged at 700 °C for 12 h shows no transformation before the applied stress level of 300 MPa. As the stress levels increase to 400 MPa, the sample shows the shape memory effect and displayed 0.8% recoverable strain at a stress level of 400 MPa. The samples are failures during the 500 MPa cycle. The observed recoverable strain values were lower than those that were theoretically predicted, which was possibly due to the larger volume fraction of high-angle grain boundary and the slightly lower than expected average grain size. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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12 pages, 2317 KiB  
Article
Hetero-Deformation Induced Hardening in a CoCrFeNiMn High-Entropy Alloy
by Hamed Shahmir, Parham Saeedpour, Mohammad Sajad Mehranpour, Seyed Amir Arsalan Shams and Chong Soo Lee
Crystals 2023, 13(5), 844; https://doi.org/10.3390/cryst13050844 - 19 May 2023
Cited by 8 | Viewed by 2239
Abstract
One of the most important issues in materials science is to overcome the strength–ductility trade-off in engineering alloys. The formation of heterogeneous and complex microstructures is a useful approach to achieving this purpose. In this investigation, a CoCrFeNiMn high-entropy alloy was processed via [...] Read more.
One of the most important issues in materials science is to overcome the strength–ductility trade-off in engineering alloys. The formation of heterogeneous and complex microstructures is a useful approach to achieving this purpose. In this investigation, a CoCrFeNiMn high-entropy alloy was processed via cold rolling followed by post-deformation annealing over a temperature range of 650–750 °C, which led to a wide range of grain sizes. Annealing at 650 °C led to the formation of a heterogeneous structure containing recrystallized areas with ultrafine and fine grains and non-recrystallized areas with an average size of ~75 μm. The processed material showed strength–ductility synergy with very high strengths of over ~1 GPa and uniform elongations of over 12%. Different deformation mechanisms such as dislocation slip, deformation twinning and hetero-deformation-induced hardening were responsible for achieving this mechanical property. Increasing the annealing temperature up to 700 °C facilitated the acquisition of bimodal grain size distributions of ~1.5 and ~6 μm, and the heterogeneous structure was eliminated via annealing at higher temperatures, which led to a significant decrease in strength. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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20 pages, 5422 KiB  
Article
Evaluation of Thermal Stability and Its Effect on the Corrosion Behaviour of Mg-RE Alloys Processed by High-Pressure Torsion
by Hiba Azzeddine, Abdelkader Hanna, Achour Dakhouche, Thierry Baudin, François Brisset, Yi Huang and Terence G. Langdon
Crystals 2023, 13(4), 662; https://doi.org/10.3390/cryst13040662 - 11 Apr 2023
Cited by 3 | Viewed by 1583
Abstract
The evolutions of microstructure and texture and the corrosion behaviour of low light rare-earth containing Mg-1.4Nd and low heavy rare-earth containing Mg-0.6Gd and Mg-0.4Dy (wt.%) were evaluated and compared after processing by high-pressure torsion (HPT) and isochronal annealing at 250 and 450 °C [...] Read more.
The evolutions of microstructure and texture and the corrosion behaviour of low light rare-earth containing Mg-1.4Nd and low heavy rare-earth containing Mg-0.6Gd and Mg-0.4Dy (wt.%) were evaluated and compared after processing by high-pressure torsion (HPT) and isochronal annealing at 250 and 450 °C for 1 h using electron backscatter diffraction (EBSD) and electrochemical tests in a 3.5% (wt.%) NaCl solution. The EBSD results show that dynamic recrystallisation (DRX) was restricted in the Mg-1.4Nd alloy which led to a heterogenous deformation microstructure whereas the Mg-0.6Gd and Mg-0.4Dy alloys exhibited a homogenous deformation microstructure formed mostly of equiaxed dynamically recrystallised DRX grains. The HPT processing caused the development of a deviated basal texture in the three alloys. A good thermal stability of the three alloys was noticed after annealing at 250 °C. By contrast, annealing at 450 °C led to a homogenous equiaxed microstructure and weakening of texture for the Mg-1.4Nd alloy and a heterogenous bimodal microstructure with a stable basal texture for the Mg-0.6Gd and Mg-0.4Dy alloys. The HPT-processed Mg–RE alloys exhibited an improved corrosion resistance due to grain refinement. Thereafter, the corrosion resistance of the Mg-0.6Gd and Mg-0.4Dy alloys decreased with increasing annealing temperature due to an increase in grain size while the corrosion resistance of the Mg-1.4Nd alloy was improved after annealing at 450 °C due to precipitation and texture weakening. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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25 pages, 47269 KiB  
Article
Local Microstructure and Texture Development during Friction Stir Spot of 5182 Aluminum Alloy
by Thierry Baudin, Sandrine Bozzi, François Brisset and Hiba Azzeddine
Crystals 2023, 13(3), 540; https://doi.org/10.3390/cryst13030540 - 21 Mar 2023
Cited by 7 | Viewed by 1991
Abstract
The local microstructure, texture gradient and mechanical properties through the shoulder dimension (10 mm) of upper and lower AA5182 aluminum sheets were investigated using electron backscatter diffraction (EBSD) and Vickers microhardness after friction stir spot welding (FSSW). Based on the microstructural features (mean [...] Read more.
The local microstructure, texture gradient and mechanical properties through the shoulder dimension (10 mm) of upper and lower AA5182 aluminum sheets were investigated using electron backscatter diffraction (EBSD) and Vickers microhardness after friction stir spot welding (FSSW). Based on the microstructural features (mean grain size, grain boundary type and dynamic recrystallization (DRX)), the upper sheet was found to be mainly composed of the stir zone (SZ) and thermomechanically affected zone (TMAZ) due to the high deformation induced simultaneously by the tool rotation and the shoulder download force, while the SZ, TMAZ, heat-affected zone (HAZ) and base metal (BM) were detected in the lower sheet due to the limited effect of the shoulder on the lower sheet. The texture changes, due to the nature of the deformation, demonstrated a shear-type texture at the SZ to a plane strain compression deformation type texture at the TMAZ and then a recrystallization texture at the HAZ and BM. The microhardness gradually decreased with the increasing distance from the keyhole along the SZ, TMAZ and HAZ regions. Eventually, the microstructure and microhardness evolutions were correlated based on the Hall–Petch relationship. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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18 pages, 5033 KiB  
Article
Controlling the Plastic Anisotropy of Magnesium Alloy by Tailoring the Grain Size and Yttrium Content
by Mariyappan Arul Kumar, Marcin Wroński and Irene J. Beyerlein
Crystals 2023, 13(1), 115; https://doi.org/10.3390/cryst13010115 - 8 Jan 2023
Cited by 2 | Viewed by 1889
Abstract
Hexagonal close-packed (HCP) magnesium alloys are widely used in automotive and aerospace industries due to their low density and high specific-strength. Their applicability is mainly restricted due to poor formability and pronounced plastic anisotropy. The formability is usually improved by altering the chemistry [...] Read more.
Hexagonal close-packed (HCP) magnesium alloys are widely used in automotive and aerospace industries due to their low density and high specific-strength. Their applicability is mainly restricted due to poor formability and pronounced plastic anisotropy. The formability is usually improved by altering the chemistry (adding rare-earth elements like Y) or modulating the microstructure (e.g., grain refinement). However, grain refinement alone cannot yield the desired ductility, and the scarcity of rare-earth elements also limits the extent to which the alloying strategy can be used. To overcome these issues, in this work, it is proposed that the formability of Mg alloys can be improved by combining the grain refinement and alloying approaches. To quantitively explore this possibility, a crystal-plasticity-based constitutive model, which is sensitive to both alloying concentration and grain sizes, is developed. To demonstrate, the model is applied to study the combined effect of Y content and grain size on the mechanical responses of Mg alloy. The calculations are used to build maps of plastic anisotropy measures, such as tension–compression asymmetry ratio and Lankford coefficients, for a wide range of Y content and grain sizes. From these maps, the grain size that would yield the desired performance of Mg alloy for a fixed Y content can be identified. This work provides an accelerated pathway to optimize both the microstructure and chemistry simultaneously to achieve formability and to reduce the dependence on alloying. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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Review

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17 pages, 1764 KiB  
Review
A Critical Review of von Mises Criterion for Compatible Deformation of Polycrystalline Materials
by Yan Huang and Jun Jiang
Crystals 2023, 13(2), 244; https://doi.org/10.3390/cryst13020244 - 31 Jan 2023
Cited by 10 | Viewed by 4318
Abstract
A von Mises criterion for compatible deformation states that five independent slip systems must operate for polycrystals to deform uniformly and without failure at the grain boundaries, which is supported by the Taylor–Bishop–Hill theory or simply the Taylor model, defining the laws of [...] Read more.
A von Mises criterion for compatible deformation states that five independent slip systems must operate for polycrystals to deform uniformly and without failure at the grain boundaries, which is supported by the Taylor–Bishop–Hill theory or simply the Taylor model, defining the laws of plastic deformation of polycrystalline aggregates and being one of the key cornerstones of crystal plasticity theory. However, the criterion has fundamental flaws as it is based on an unfounded correlation between phenomenological material flow behaviour in continuum mechanics and crystal structure dependent dislocation slip, and there has been no experimental evidence to show simultaneous operation of five independent slip systems. In this paper, the Von Mises criterion and the Taylor model are revisited and examined critically, and the fundamental issues related to the requirement of independent slip systems for compatible deformation and the selection of the active slip systems are addressed. Detailed analysis is performed of the stress state that eliminates the possibility of the simultaneous operation of five independent slip systems, and of the relative displacement vector due to the dislocation slip which defines the quantity of the strain that can be expressed by a strain tensor, instead of individual strain components. Discussions are made to demonstrate that although three linearly independent slip systems are essentially sufficient for compatible deformation, one slip system, being selected according to Schmidt law, dominates at a time in a characteristic domain as deformation accommodation occurs between grains or characteristic domains rather than at each point. Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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Other

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1 pages, 163 KiB  
Correction
Correction: Zhang et al. Microstructures, Mechanical Properties and Transformation Behavior in Ni49.6Ti35.4Hf15 Alloy Produced with High-Pressure Torsion. Crystals 2023, 13, 1246
by Jintao Zhang, Shibo Wang, Hua Ding, Peng Hu, Yi Huang and Yu Zhang
Crystals 2024, 14(1), 8; https://doi.org/10.3390/cryst14010008 - 21 Dec 2023
Viewed by 847
Abstract
In the original publication [...] Full article
(This article belongs to the Special Issue Crystal Plasticity (Volume III))
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