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1
Sundeev, R. V., A. M. Glezer e A. V. Shalimova. "Phase Transformations «Amorphization ↔ Crystallization» In Metallic Materials Induced by Severe Plastic Deformation". REVIEWS ON ADVANCED MATERIALS SCIENCE 54, n. 1 (1 marzo 2018): 93–105. http://dx.doi.org/10.1515/rams-2018-0021.
Abstract (sommario):
Abstract In this review we are considered systematically the phenomenon of deformation-induced phase transformations from crystalline intermetallic compounds and complex phases to amorphous state and vice versa phase transformations from amorphous state to crystalline one upon severe plastic deformation at different temperatures. The nature and structural features of these transitions essentially for high pressure torsion deformation are analyzed in the frame of basic principles of nonequilibrium thermodynamics. The effects of phase cycling and a stationary amorphous - nanocrystalline state formation at significant deformations is discussed in details.
2
Carter, Karen E. "Grenville orogenic affinities in the Red Mountain area, Llano Uplift, Texas". Canadian Journal of Earth Sciences 26, n. 6 (1 giugno 1989): 1124–35. http://dx.doi.org/10.1139/e89-096.
Abstract (sommario):
The Red Mountain area in the southeast corner of the Llano Uplift contains evidence of a Grenville-age, polyphase, non-coaxial deformational history. Four synmetamorphic deformational phases affected the Precambrian Click Formation of the Packsaddle Group, and a single shear-related deformation is observed in the Big Branch and Red Mountain gneisses. The first phase of deformation produced tight folds with an axial–planar metamorphic foliation. The second, and most intense, pervasive deformational phase produced the regional metamorphic layering, isoclinal folds, transposition of bedding, and mylonitic textures in the gneisses. The third deformation is characterized by tight to isoclinal, north-verging folds with an axial–planar differentiation crenulation cleavage. The fourth phase of deformation resulted in a north-northwest-trending differentiation crenulation cleavage that is axial–planar to small east-northeast-verging folds. The growth of cordierite over all foliations indicates that low-pressure metamorphism postdated all four deformational phases.The second deformation had begun at the latest by 1167 ± 2 Ma, the age of metamorphism of the gneisses, and before the intrusion of melarhyolite dikes dated at 1080 ± 30 Ma. Thus, the orogenic event(s) responsible for the complex deformational and metamorphic history is Grenvillian in age.
3
Cui, Ya, Zhi Min Zhang, Jian Min Yu e Qiang Wang. "Research on Multiple Plastic Deformations of Ultra-High Strength Aluminium Alloy". Advanced Materials Research 652-654 (gennaio 2013): 1132–37. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1132.
Abstract (sommario):
Research on multipass plastic deformation of 7A04 ultra-high strength aluminium alloy by isothermal compression experiments on the 6300KN extrusion press. Experiment results show that elongation reaches its maximal value 9.25% after the first deformation. It is obvious that fibrous tissues appeared along the metal flow direction in the deformed 7A04 ultra-high aluminium alloy, with heterogeneous distribution of precipitated η (MgZn2) phase in the matrix, which results in lower strength (Rm=335MPa, Re=212.5MPa). As the times of deformation increases, precipitated phases grow gradually and the plasticity of alloys decreases dramatically, which reaches its minimal value 5.17% after the fourth deformation. With η(MgZn2) phase disperses gradually, the strength of the alloy increases gradually, and reaches its maximal value 386.7MPa after the fourth deformations. It is proved that 7A04 high-strength aluminium alloy has better synthetic mechanical properties after four times deformation.
4
Nurdin, N., D. Pujiastuti e M. Marzuki. "Analysis of vertical seismic deformation of the 2018 Palu earthquake using Global Navigation Satellite System (GNSS) data". Journal of Physics: Conference Series 2596, n. 1 (1 settembre 2023): 012037. http://dx.doi.org/10.1088/1742-6596/2596/1/012037.
Abstract (sommario):
Abstract The vertical seismic deformation of the Palu earthquake magnitude of 7.4 on the Richter Scale, which occurred on September 28, 2018, has been analyzed using InaCORS (Indonesian Continuously Operating Reference Stations) stations. The stations used are CBAL, PALP, CTOL, CMLI, CPAL, and CBIT. The analysis was conducted using GAMIT, GLBOK, and GMT software. The analysis focused on the period of 100 days, starting from August 6, 2018 (DoY 218) to November 28, 2018 (DoY 318), encompassing the preseismic, coseismic, and post-seismic phases. During the preseismic phase (DoY 218-270), the InaCORS stations experienced a slight deformation ranging from -10.9353 mm to 6.5525 mm. Tectonic manifestations influenced the direction of movement in Sulawesi. The deformation significantly increased in the coseismic phase (DoY 271-272). The InaCORS stations experienced deformations ranging from -169.8 mm to 8.755 mm, which differed in the direction from the preseismic phase. The stations in the northern region predominantly moved towards the north, while those in the southern region moved towards the south. During the post-seismic phase (DoY 273-318), the movement of the InaCORS stations followed the direction of deformation observed in the coseismic phase. However, the displacement was relatively smaller, ranging from 11.5909 mm to 17.23733 mm.
5
Ni, Peishuang, Yanyang Liu, Hao Pei, Haoze Du, Haolin Li e Gang Xu. "CLISAR-Net: A Deformation-Robust ISAR Image Classification Network Using Contrastive Learning". Remote Sensing 15, n. 1 (21 dicembre 2022): 33. http://dx.doi.org/10.3390/rs15010033.
Abstract (sommario):
The inherent unknown deformations of inverse synthetic aperture radar (ISAR) images, such as translation, scaling, and rotation, pose great challenges to space target classification. To achieve high-precision classification for ISAR images, a deformation-robust ISAR image classification network using contrastive learning (CL), i.e., CLISAR-Net, is proposed for deformation ISAR image classification. Unlike traditional supervised learning methods, CLISAR-Net develops a new unsupervised pretraining phase, which means that the method uses a two-phase training strategy to achieve classification. In the unsupervised pretraining phase, combined with data augmentation, positive and negative sample pairs are constructed using unlabeled ISAR images, and then the encoder is trained to learn discriminative deep representations of deformation ISAR images by means of CL. In the fine-tuning phase, based on the deep representations obtained from pretraining, a classifier is fine-tuned using a small number of labeled ISAR images, and finally, the deformation ISAR image classification is realized. In the experimental analysis, CLISAR-Net achieves higher classification accuracy than supervised learning methods for unknown scaled, rotated, and combined deformations. It implies that CLISAR-Net learned more robust deep features of deformation ISAR images through CL, which ensures the performance of the subsequent classification.
6
Skorupska, Monika, Mariusz Kulczyk, Piotr Denis, Dominik Grzęda, Anna Czajka e Joanna Ryszkowska. "Structural Hierarchy of PA6 Macromolecules after Hydrostatic Extrusion". Materials 16, n. 9 (28 aprile 2023): 3435. http://dx.doi.org/10.3390/ma16093435.
Abstract (sommario):
This article presents the influence of severe plastic deformation by hydrostatic extrusion (HE) on the thermal and structural properties of polyamide 6 (PA6). During the hydrostatic extrusion process, a fibrous structure oriented along the extrusion direction is formed, which was visualized during microscopic observations. The degree of crystallinity was analyzed by differential scanning calorimetry (DSC). Wide-angle X-ray scattering diffraction (WAXS) analysis was used to partially characterize the PA6 structure after the HE process. The contents of various forms of the crystalline phase in PA6 samples before and after the HE process were analyzed in fragments of spectroscopy in infrared (FTIR). The favorable properties of PA6 after the HE process were obtained after deformation under conditions generating an adiabatic temperature higher than the glass transition temperature and lower than the temperature of the onset of melting of the crystalline phase. Thermal analysis using DSC allowed us to conclude that in the PA6 after the HE process generating deformations in the range of 0.68–1.56, the proportion of the crystalline phase α increases in PA6. As the deformation increases in the HE process, the crystalline phase proportion increases by 12% compared to the initial material (before HE). The glass transition temperature of PA6 is ca. 50.6 °C, reduced for the sample after the HE process at a small deformation of 0.68 (PA6_0.68) to ca. 44.2 °C. For other samples, Tg is ca. 53.2–53.5 °C. As a result of the analysis of WAXS diffractograms of PA6 samples after various deformations in the HE process, the presence of typical peaks of phases α1 and α2 and γ was observed. The results of the FTIR spectroscopic analysis confirm these observations that as the deformation increases, the proportion of the crystalline phase α increases.
7
Ryś, Janusz, e Anna Zielińska-Lipiec. "Structural Aspects of Ferrite and Austenite Co-Deformation in Duplex Stainless Steel". Solid State Phenomena 203-204 (giugno 2013): 28–33. http://dx.doi.org/10.4028/www.scientific.net/ssp.203-204.28.
Abstract (sommario):
The present research is a part of project dealing with structural aspects of ferrite and austenite co-deformation in duplex stainless steels. The examination concerned a development of ferrite and austenite microstructures, major deformation mechanisms operating in both phases and texture formation upon cold-rolling of a model duplex type steel. The investigations showed that the band-like morphology of two-phase structure formed upon processing together with specific starting textures obtained after a preliminary thermo-mechanical treatment exerted significant influence on texture and microstructure development in both constituent phases. Microstructure and texture evolution in examined duplex steel significantly differed from those in one-phase steels. These differences resulted first of all from the role of the phase boundaries acting as the barriers for dislocation movement and affecting the processes of strain localization at higher deformations.
8
Pereloma, Elena, e Ilana Timokhina. "Deformation-Induced Phase Transformations". Metals 8, n. 11 (31 ottobre 2018): 886. http://dx.doi.org/10.3390/met8110886.
9
Hall, Ernest L., e James D. Livingston. "Deformation modes in Laves phase intermetallics". Proceedings, annual meeting, Electron Microscopy Society of America 47 (6 agosto 1989): 318–19. http://dx.doi.org/10.1017/s0424820100153567.
Abstract (sommario):
There is at present a large amount of interest in the mechanical behavior of intermetallic alloys, and one of the largest classes of these alloys are the Laves phases. There are three basic types of Laves phases: cubic (C15), hexagonal (C14), and dihexagonal (C36), with stacking sequences on the close-packed planes of ABCABC..., ABAB..., and ABAC..., respectively, where each capital letter represents an interpenetrating four-atomic-layer unit. This structural complexity gives rise to a special mode of deformation for Laves phases, called synchroshear, which requires the cooperative movement of adjacent layers in different directions. Very little work has been done to date on the deformation modes in Laves phases because of the inherent brittleness of these materials at room temperature. However, through alloying it is possible to obtain mixtures of the various Laves phase types, and to affect such properties as stacking fault energy, and thus opportunities may exist for increasing ductility. In this study, the deformation microstructures of different Laves phase types were explored.
10
Huang, Zengshu, Jinping Sun, Qing Li, Weixian Tan, Pingping Huang e Yaolong Qi. "Time- and Space-Varying Atmospheric Phase Correction in Discontinuous Ground-Based Synthetic Aperture Radar Deformation Monitoring". Sensors 18, n. 11 (11 novembre 2018): 3883. http://dx.doi.org/10.3390/s18113883.
Abstract (sommario):
Ground-based synthetic aperture radar (GB-SAR) uses active microwave remote-sensing observation mode to achieve two-dimensional deformation measurement and deformation trend extraction, which shows great prospects in the field of deformation monitoring. However, in the process of GB-SAR deformation monitoring, the disturbances caused by atmospheric effect cannot be neglected, and the atmospheric phases will seriously affect the precision of deformation monitoring. In discontinuous GB-SAR deformation monitoring mode, the atmospheric phases are particularly affected by changes of time and space, so the traditional models of atmospheric phase correction are no longer applicable. In this paper, the interferometric phase signal model considering atmospheric phase is first established. Then, the time- and space-varying characteristics of the atmospheric phase are analyzed, and a novel time- and space-varying atmospheric phase correction algorithm, based on coherent scatterers analysis, is proposed. Finally, slope deformation monitoring experiments are carried out to verify the validity and robustness of the proposed algorithm.
11
Cayzer, Nicola J., Shoko Odake, Ben Harte e Hiroyuki Kagi. "Plastic deformation of lower mantle diamonds by inclusion phase transformations". European Journal of Mineralogy 20, n. 3 (29 maggio 2008): 333–39. http://dx.doi.org/10.1127/0935-1221/2008/0020-1811.
12
Fashanu, T. A., A. T. Adebusoye, A. A. Oyediran e O. O. Adewumi. "Dynamic analysis of the large strain deformation of flexible pipes conveying two-phase fluids. Part II: nonlinear vibration analysis". Nigerian Journal of Technology 42, n. 1 (8 maggio 2023): 130–35. http://dx.doi.org/10.4314/njt.v42i1.16.
Abstract (sommario):
This work presents the nonlinear analysis of the dynamics of large strain deformation of subsea flowlines and jumpers conveying two-phase fluid. Precisely, flexible pipes operating in the stated condition undergo large strain deformations. Thus, the known nonlinear deterministic model of the system is solved using method of discretized perturbation. Precisely, this study obtained the nonlinear natural frequency of simply supported flexible pipes modelled using the large strain deformation theory. Results show that both hardening and softening nonlinear behaviors are indicated for pipe undergoing large strain deformation compared with deformations modelled with small strain theory. Thus, operational insights and parameters for sustainable management of large strain deformed subsea flow lines and jumpers conveying two phase flow are made available.
13
Wang, Zhihong, Huayang Dai, Yueguan Yan, Jintong Ren, Yanjun Zhang e Jibo Liu. "An InSAR Deformation Phase Retrieval Method Combined with Reference Phase in Mining Areas". Remote Sensing 15, n. 18 (17 settembre 2023): 4573. http://dx.doi.org/10.3390/rs15184573.
Abstract (sommario):
The acquisition of precise deformation data, including the entirety of the subsidence basin resulting from subterranean mining operations, assumes critical significance in the context of surface impairment monitoring during the course of mining activities. In light of the constraints associated with InSAR technology when applied to the surveillance of expansive deformation gradient mining regions, an innovative approach is advanced herein for InSAR deformation phase retrieval. This approach integrates a reference phase, derivable through a variety of means, including pre-existing models or measurements. Initially, the reference deformation phase is subjected to subtraction from the wrapped InSAR deformation phase, culminating in the derivation of the wrapped phase indicative of the residual phase. Notably, it is posited that the fringe density characterizing the wrapped phase of the residual phase is theoretically diminished in comparison to that of the InSAR wrapped phase. This reduction in complexity in phase unwrapping ensues as a direct consequence. Subsequent to this, the phase retrieval process is effectuated through the summation of the reference phase and the unwrapped phase pertaining to the residual phase. The study harnesses Sentinel-1A and ALOS PALSAR-2 data, employing the PIM-predicted outcomes and GNSS-RTK monitoring outcomes as reference phases for the execution of phase retrieval experiments in two designated study areas. The computation of subsidence is subsequently realized through the combination of the displacement vector depression angle model and the retrieved phase, with the accuracy thereof corroborated through the utilization of leveling data. The experimental findings underscore the efficacy of the reference phase retrieval methodology in securing a more precise deformation phase characterization within expansive deformation gradient mining regions, thereby demonstrating the suitability of this methodological approach.
14
Perez-Payan, Sinuhe, M. Sabido, E. Mena e C. Yee-Romero. "Analysis of Scalar Field Cosmology with Phase Space Deformations". Advances in High Energy Physics 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/958137.
Abstract (sommario):
Phase space deformations on scalar field cosmology are studied. The deformation is introduced by modifying the symplectic structure of the minisuperspace variables. The effects of the deformation are studied in the “C-frame” and the “NC-frame.” In order to remove the ambiguities of working on different frames, a new principle is introduced. When we impose that both frames should be physically equivalent, we conclude that the only possibility for this model, is to have an effective cosmological constantΛeff≥0. Finally we bound the parameter space forθandβ.
15
Wang, Yanju, Zhao Zhang, Xinhao Wang, Yanfeng Yang, Xiang Lan e Heng Li. "Crystal Plasticity Finite Element Modeling on High Temperature Low Cycle Fatigue of Ti2AlNb Alloy". Applied Sciences 13, n. 2 (4 gennaio 2023): 706. http://dx.doi.org/10.3390/app13020706.
Abstract (sommario):
Ti2AlNb alloy is a three-phase alloy, which consists of O phase, β phase and α2 phase. Because of the difference in the mechanical characteristics between phases, Ti2AlNb alloy often exhibits deformation heterogeneity. Based on EBSD images of the Ti2AlNb alloy, a crystal plasticity finite element model (CPFEM) was built to study the effects of O phase and β phase (dominant phases) on stress and strain distribution. Four types of fatigue experiments, and the Chaboche model with 1.2%~1.6% total strain range were conducted to verify the CPFEM. The simulation results showed that the phase boundary was the important position of stress concentration. The main reason for the stress concentration was the inconsistency deformation of grains which resulted from the different deformation abilities of the O and β phases.
16
Livingston, J. D., e E. L. Hall. "Room-temperature deformation in a Laves phase". Journal of Materials Research 5, n. 1 (gennaio 1990): 5–8. http://dx.doi.org/10.1557/jmr.1990.0005.
Abstract (sommario):
Transmission electron microscopy of two-phase V-Hf-Nb and V-Hf-Nb-Ti alloys plastically deformed at room temperature shows that {111} (112) twinning is a major deformation mode for the HfV2-based Laves phase. Bands of concentrated shear are also observed. Possible approaches to enhance low-temperature deformability in other Laves phases are discussed.
17
Gusev, Alexander. "Phase Transition at the Metric Elastic Universe". Symposium - International Astronomical Union 168 (1996): 569–70. http://dx.doi.org/10.1017/s007418090011071x.
Abstract (sommario):
At the last time the concept of the curved space-time as the some medium with stress tensor σαβon the right part of Einstein equation is extensively studied in the frame of the Sakharov - Wheeler metric elasticity(Sakharov (1967), Wheeler (1970)). The physical cosmology pre- dicts a different phase transitions (Linde (1990), Guth (1991)). In the frame of Relativistic Theory of Finite Deformations (RTFD) (Gusev (1986)) the transition from the initial stateof the Universe (Minkowskian's vacuum, quasi-vacuum(Gliner (1965), Zel'dovich (1968)) to the final stateof the Universe(Friedmann space, de Sitter space) has the form of phase transition(Gusev (1989) which is connected with different space-time symmetry of the initial and final states of Universe(from the point of view of isometric groupGnof space). In the RTFD (Gusev (1983), Gusev (1989)) the space-time is described by deformation tensorof the three-dimensional surfaces, and the Einstein's equations are viewed as the constitutive relations between the deformations ∊αβand stresses σαβ. The vacuum state of Universe have the visible zero physical characteristics and one is unsteady relatively quantum and topological deformations (Gunzig & Nardone (1989), Guth (1991)). Deformations of vacuum state, identifying with empty Mikowskian's space are described the deformations tensor ∊αβ, wherethe metrical tensor of deformation state of 3-geometry on the hypersurface, which is ortogonaled to the four-velocityis the 3 -geometry of initial state,is a projection tensor.
18
PODIO-GUIDUGLI, PAOLO, e GIORGIO VERGARA CAFFARELLI. "EQUILIBRIUM PHASES AND LAYERED PHASE MIXTURES IN ELASTICITY". Mathematical Models and Methods in Applied Sciences 02, n. 02 (giugno 1992): 143–66. http://dx.doi.org/10.1142/s0218202592000107.
Abstract (sommario):
In this paper an equilibrium phase is a restriction of a piecewise-affine deformation of a body to a (maximal, connected) subbody whose deformation is affine; a layered phase mixture is a continuous deformation that admits at least two distinct phases, separated by a plane interface. We study equilibrium phases and layered phase mixtures in the context of finite elasticity, in the presence of three different boundary conditions of traction: uniform pressure, and two other of null Lagrangians. In Part I we reduce to a unique format the stationarity condition for the existence of equilibrium phases — of the conformal, transversely symmetric and asymmetric types — in elastic materials of arbitrary mechanical response; and we determine reasonable assumptions under which the stationary points of a (generalized) free energy are indeed equilibrium phases. In Part II we restrict attention to isotropic material, and give explicit stationarity and compatibility conditions for the existence of mixtures of two layered, transversely symmetric phases.
19
Li, Bing, Qianqian Fu, Rongzhou Yu, Zikai Lin, Jun Wang, Xue Wang, Renguo Guan e Jiehua Li. "Two-Phase Flow Coordination Characteristics of H62 Brass Alloy Prepared by Up-Drawing Continuous Casting". Metals 13, n. 3 (15 marzo 2023): 599. http://dx.doi.org/10.3390/met13030599.
Abstract (sommario):
In this study, the two-phase flow coordination characteristics between α and β phases of H62 brass made by up-drawing continuous casting are investigated based on the upsetting process. An in situ and new research method for two-phase flow is put forward, and the two-phase flow and grain refinement characteristics are observed under different deformation conditions. The results show that α phase flows fast under 400 °C, β phase is pulled and overridden by α phase under this temperature. When the temperature increases to 500 °C, which is higher than β phase transition temperature, the flow velocity of β phase increases, and the deformation of β phase is found to bulge. The flow of β phase is more sensitive to low deformation rates than α phase. The deformation amount has a more significant impact on β phase than α phase, and the deformation of β phase promotes the grain fragmentation and refinement of α phase accompanied by huge β phase bulging obviously. Under the conditions of high temperature, low deformation rate, and large deformation amount, both phase α and β of up-drawing continuous casting brass alloy are broken and the grains are refined. Based on the two-phase flow characteristic, numerical simulation is used to obtain the optimal continuous extrusion parameters of the H-shaped wire of up-drawing continuous casting H62 brass. Then, the optimized complex cross-section wire is prepared by continuous extrusion experiment. This research aims to provide guidance for the complex processing of two-phase alloys.
20
Niinomi, Mitsuo. "Enhancement of Mechanical Biocompatibility of Titanium Alloys by Deformation-Induced Transformation". Materials Science Forum 879 (novembre 2016): 125–30. http://dx.doi.org/10.4028/www.scientific.net/msf.879.125.
Abstract (sommario):
Metastable β-type titanium alloys are highly suitable for use as structural biomaterials applied to hard tissue, i.e., as cortical bone (hereafter, bone) replacing implants. However, their mechanical biocompatibitities, such as the Young’s modulus, strength and ductility balance, fatigue strength, resistance against fatigue crack propagation and fracture toughness, require improvenent for increased compatibility with bone. Through deformation, the metastable β-phase in a metastable β-type titanium alloy is transformed into various phases, such as α’ martensite, α” martensite, and ω-phases with exact phase depending by metastable β-phase stability. In addition, twinning is also induced by deformation. Deformation twinning effectively enhances the work hardening in the metastable β-type titanium alloy, leading to increased strength and ductility. This improvement is accompanied by with other deformation-induced transformations including the appearance of deformation-induced martensite and ω-phase transformation. The enhancement of the mechanical biocompatibility of various materials using the abovementioned deformation-induced transformation is described in this paper, for both newly developed metastable β-type Ti-Mo and Ti-Cr alloys for biomedical applications.
21
Ryś, J., e A. Zielińska-Lipiec. "Deformation of Ferrite-Austenite Banded Structure in Cold-Rolled Duplex Steel / Odkształcenie Pasmowej Struktury Ferrytu I Austenitu W Walcowanej Na Zimno Stali Duplex". Archives of Metallurgy and Materials 57, n. 4 (1 dicembre 2012): 1041–53. http://dx.doi.org/10.2478/v10172-012-0116-2.
Abstract (sommario):
Duplex type ferritic-austenitic stainless steels develop a specific two-phase banded structure upon thermo-mechanical pre-treatment and subsequent cold-rolling. The band-like morphology of ferrite and austenite imposes different conditions on plastic deformation of both constituent phases in comparison to one-phase ferritic and austenitic steels. In the present research the ingot of a model ferritic-austenitic steel of duplex type, produced by laboratory melt, was subjected to preliminary thermo-mechanical treatment including forging and solution annealing. Afterwards cold-rolling was conducted over a wide deformation range. The investigations comprised examination of ferrite and austenite microstructures by means of optical and transmission electron microscopy and texture measurements after selected rolling reductions. The presented results indicate that deformation mechanisms operating within the bands of both constituent phases are essentially the same as compared to one-phase steels, however their appearance and contribution are changed upon deformation of two-phase banded structure. Different deformation behavior within ferrite-austenite bands in duplex steels, visible especially at higher strains, considerably affects microstructure evolution and in consequence texture formation in both phases.
22
Laudal, Olav Arnfinn. "Phase Spaces and Deformation Theory". Journal of Generalized Lie Theory and Applications 5 (2011): 1–18. http://dx.doi.org/10.4303/jglta/g110104.
23
Lindop, J. E., G. M. Treece, A. H. Gee e R. W. Prager. "Phase-based ultrasonic deformation estimation". IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 55, n. 1 (gennaio 2008): 94–111. http://dx.doi.org/10.1109/tuffc.2008.620.
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Laudal, Olav Arnfinn. "Phase Spaces and Deformation Theory". Acta Applicandae Mathematicae 101, n. 1-3 (25 gennaio 2008): 191–204. http://dx.doi.org/10.1007/s10440-008-9192-8.
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Ankem, Sreeramamurthy, William J. Joost e Samuel C. Schwarm. "Recent Advances on the Deformation Behavior of Two-Phase α+β Titanium Alloys". Materials Science Forum 950 (aprile 2019): 55–59. http://dx.doi.org/10.4028/www.scientific.net/msf.950.55.
Abstract (sommario):
Two-phase materials, such as α+β Titanium (Ti) alloys, are technologically important. A number of factors can affect deformation behavior, including the interaction stresses between phases, the crystallographic relationships between phases, and the morphology. As a result, the deformation mechanisms of two-phase alloys may be different from the individual single-phase materials. For example, twinning may not occur in a single phase material if the grain size is very small but twinning can occur in a very fine grained alloy if the second phase contributes to the interfacial stresses due to elastic interactions. Interaction stresses can result from the difference in the elastic properties of the two phases. In particular, these elastic interaction stresses can be quantified by the finite element method (FEM). In this paper recent developments regarding two-phase deformation mechanisms will be reviewed and the ramifications on mechanical behavior in regard to two-phase Ti alloys in particular and on two-phase metallic materials in general will be outlined.
26
TAKADA, NAOKI, AKIO TOMIYAMA e SHIGEO HOSOKAWA. "LATTICE BOLTZMANN SIMULATION OF INTERFACIAL DEFORMATION". International Journal of Modern Physics B 17, n. 01n02 (20 gennaio 2003): 179–82. http://dx.doi.org/10.1142/s0217979203017308.
Abstract (sommario):
This study describes the numerical simulations of two-phase interfacial deformations using the binary fluid (BF) model in the lattice Boltzmann method (LBM), where a macroscopic fluid involves mesoscopic particles repeating collisions and propagations and an interface is reproduced in a self-organizing way by repulsive interaction between different kinds of particles. Schemes for the BF model are proposed to simulate motions of immiscible two phases with different mass densities. For higher Reynolds number, the finite difference-based lattice Boltzmann scheme is applied to the kinetic equations of particles, which include convection terms to reduce the diffusivity of each phase volume. In addition, two parameters are introduced into the BF model to adjust surface tension and interfacial thickness independently. The numerical results of three-dimensional bubble motion under gravity and two-dimensional droplet deformation under shear stress indicate that the lattice-Boltzmann BF model with the proposed schemes would be applicable to simulating interfacial dynamics of immiscible two-phase fluids.
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Costa, Bruno de Siqueira, Carlos Humberto da Silva e Ana Cláudia Dantas da Costa. "Structural characterization of the internal domain of Paraguai Belt, in the Cangas region, south central portion of Mato Grosso, Brazil". Brazilian Journal of Geology 45, n. 1 (marzo 2015): 35–49. http://dx.doi.org/10.1590/23174889201500010003.
Abstract (sommario):
The structural study of rocks in the district of Cangas showed the identification of three phases of deformation for the Cuiabá Group in this region. The main structure oriented 120/27 is related to the first phase of deformation defined by a slate cleavage, parallel to the bedding and to the axial plane of recumbent folds. In the early stages of this phase a family of quartz veins (V1) was generated, arranged parallel to the structures of this phase of deformation, being all almost deformed. The second phase of deformation formed a crenulation cleavage (Sn+1), axial plane of opened to gentle and asymmetric normal folds, with preferential orientation 110/68. The third phase of deformation is represented by a set of centimetric to decametric scale fractures and faults with metric slip that cut all previous structures, with orientations 35/82. Related to this phase of deformation occurs a second family of quartz veins (V2), which fills the fractures related to Dn+2 and may or may not be carrying gold mineralization.
28
Li, Kejian, Qiang Zheng, Chunhong Li, Bin Shao, Donglin Guo, Dengming Chen, Jianchun Sun, Jiling Dong, Pengjun Cao e Keesam Shin. "Characterization of Surface Modification of 347 Stainless Steel upon Shot Peening". Scanning 2017 (2017): 1–4. http://dx.doi.org/10.1155/2017/2189614.
Abstract (sommario):
Plastic deformations, such as those obtained by shot peening on specimen surface, are an efficient way to improve the mechanical behavior of metals. Generally, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) are commonly used to observe the complex microstructural evolutions, such as grain refinement and phase transformation, induced by the surface treatment. In this work, the microstructure of 347 stainless steel, after ultrasonic shot peening (USP) treatments, was investigated. SEM, EBSD, transmission electron microscopy, and X-ray diffraction were used to observe the microstructural evolutions, such as grain refinement and phase transformation. Deformation depth after the USP treatment was about 200 μm. Grain size on the treated surface layer was about 100 nm, with two phases: austenite and α′-martensite. The percentages of the austenite and α′-martensite phases were 54% and 46%, respectively, which constitute an exact expression of the degree of plastic deformation on austenitic stainless steel.
29
Ryś, Janusz, e Małgorzata Witkowska. "Microstructure and Deformation Behavior of Cold-Rolled Super-Duplex Stainless Steel". Solid State Phenomena 163 (giugno 2010): 151–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.163.151.
Abstract (sommario):
The present examination is a part of project concerning a deformation behavior of duplex type ferritic-austenitic stainless steels. The investigations included the analysis of ferrite and austenite microstructures formed in cold-rolled sheet of super-duplex stainless steel, major deformation mechanisms operating in both constituent phases and changes in morphology of two-phase structure after the thermo-mechanical treatment and subsequent cold-rolling. Duplex type stainless steels develop the band-like ferrite-austenite morphology in the course of hot- and cold-rolling. This specific two-phase structure creates different conditions for plastic deformation in comparison to single phase steels. The interaction of both phases upon deformation exerts fairly significant influence on structure and texture formation in both constituent phases and in consequence affects the material properties and its behavior upon further processing.
30
Blinova, Elena N., Alexander M. Glezer, M. A. Libman e E. V. Pimenov. "Influence of Severe Plastic Deformations on Martensitic Transformation in Alloys of Fe-Cr-Ni System". Key Engineering Materials 910 (15 febbraio 2022): 802–7. http://dx.doi.org/10.4028/p-3g2085.
Abstract (sommario):
The article investigates influence of large plastic deformations created in the Bridgman anvils on the mechanical properties and microstructure of metastable alloys of the iron-chromium-nickel system of the austenitic-martensitic class. It is found that the application of deformation in the Bridgman anvils with a true logarithmic deformation e = 6-7 leads to formation of the α-phase (deformation martensite) with significantly higher mechanical properties compared to martensite formed during deformation by linear rolling. The authors reveal the differences in the microstructure of the alloy after deformation in the Bridgman anvils and deformation by rolling, which explain the discovered effect.
31
Chen, Wen, Peng Zhang, Jing Xie, Yang Liu e Wenxia Zhao. "The Effect of Nb Content on Microstructure Evolution of GH4169 superalloy During Hot Deformation". MATEC Web of Conferences 358 (2022): 01001. http://dx.doi.org/10.1051/matecconf/202235801001.
Abstract (sommario):
This research conducted a thermal compression deformation test on two GH4169 alloy samples with 5.40wt% and 5.21wt% Nb contents respectively, under deformation temperatures ranging from 900°C to 1030°C and the strain rates of 0.04s-1, 0.08s-1. Data from the deformation test were used to study the effects of deformation temperature and strain rate on the microstructure, δ phase morphology, and δ phase evolution of both alloy samples, so as to reveal the structural evolution mechanism. The results show that the long needle-like δ phase in the alloy microstructure with high Nb content undergoes deformation fracture and decomposition fracture during deformation and compression under high temperature, with the fracture decomposition temperature being 990°C. Moreover, microstructures of alloys with low Nb content were dominated by granular δ phases; as the deformation temperature increases or the strain rate decreases, the content of the δ phase gradually decreases, causing the alloy’s dynamic recrystallization grain size and dynamic recrystallization volume fraction to gradually increase from deformation twins at low temperatures to complete recrystallization at high temperatures.
32
Sato, Hisashi, Takayuki Nishiura, Eri Miura-Fujiwara e Yoshimi Watanabe. "Phase Transformation in Fe Alloys Induced by Surface Treatment". Materials Science Forum 706-709 (gennaio 2012): 1996–2001. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.1996.
Abstract (sommario):
Difference of the phase transformation behavior at deformation-induced layer depending on surface treatment methods was investigated using Fe-33mass%Ni alloy. As specimens, two kinds of specimens were prepared. One specimen has austenite (γ) single structure, and the other specimen consists of both martensite (α’) and γ phases. Using these specimens, shot-peening tests were performed, and then phase transformation behavior induced by the shot-peening was compared with that by sliding wear reported in previous literature. The deformation-induced layer induced by shot-peening has very fine microstructure consisted of both α’ and γ phases. The microstructure in the deformation-induced layer formed by shot-peening becomes similar with increasing duration of shot-peening regardless of initial microstucture. On the other hand, the deformation-induced layer induced by sliding wear is reported to have γ single structure regardless of initial microstructure. This microstructural difference between shot-peening and sliding wear comes from the difference of heat generation during the surface treatment. Therefore, it is concluded that phase transformation behavior in deformation-induced layer depends on surface treatment method.
33
Despax, Laurie, Vanessa Vidal, Denis Delagnes, Moukrane Dehmas, Hiroaki Matsumoto e Vincent Velay. "Mechanical behaviour and microstructural evolution in fine grain Ti-6Al-4V alloy under superplastic conditions". MATEC Web of Conferences 321 (2020): 11011. http://dx.doi.org/10.1051/matecconf/202032111011.
Abstract (sommario):
Ti-6Al-4V is able to support high level of deformations like superplastic deformation for aeronautical structural applications. However, the applied temperature during forming induces changes in phase fraction, which may have an impact on the mechanisms of deformation involved and the final part. Mechanisms described in the literature, like dislocation glide, diffusional creep, Grain Boundary Sliding (GBS) accommodated by dislocation or diffusion, are still controversial as there are mainly based on post mortem analysis or on stress-strain data. The purpose of this work was to combine interrupted tensile tests and heat treatments to improve the understanding of the mechanisms of deformation on each stage of deformation. The chosen test temperatures were 750°C and 920°C which correspond to different β phase fractions. The microstructural features like grain size and phase fraction were studied by Scanning Electron Microscope (SEM) combined with image analysis. Moreover, EBSD was used to follow the change of crystalline orientation of α grains to distinguish the involved mechanisms as a function of the deformation. Indeed, it would appears that several mechanisms could be activated depending on the deformation stage and on the temperature.
34
Abrosimova, Galina, Boris Gnesin, Dmitry Gunderov, Alexandra Drozdenko, Danila Matveev, Bogdan Mironchuk, Elena Pershina, Ilia Sholin e Alexandr Aronin. "Devitrification of Zr55Cu30Al15Ni5Bulk Metallic Glass under Heating and HPT Deformation". Metals 10, n. 10 (5 ottobre 2020): 1329. http://dx.doi.org/10.3390/met10101329.
Abstract (sommario):
The nanocrystal formation in Zr55Cu30Al15Ni5 bulk metallic glass was studied under heat treatment and deformation. The activation energy of crystallization under heating is 278 kJ/mol. Different crystalline phases were found to be formed during crystallization under heating and deformation. At the first crystallization stage, the metastable phase with a hexagonal structure (lattice of space group P63/mmc with the parameters a = 8.66 Å, c = 14.99 Å) is formed under heat treatment. When the temperature rises, the metastable phase decays with the formation of stable crystalline phases. The crystalline Zr2Cu phase with the lattice of space group Fd3m is formed during crystallization under the action of deformation. It was determined that during deformation nanocrystals are formed primarily in the subsurface regions of the samples.
35
GUBENKO, S. I., E. V. PARUSOV e I. M. CHUIKO. "CRACK INITIATION ALONG THE INTERPHASE BOUNDARIES OF THE “PHASE SIDE BY SIDE” TYPE HETEROPHASE INCLUSIONS". Physical Metallurgy and Heat Treatment of Metals 1, n. 1 (96) (4 giugno 2022): 24–31. http://dx.doi.org/10.30838/j.pmhtm.2413.240422.24.839.
Abstract (sommario):
Purpose of research. Investigation into crack initiation features in heterophase inclusions of the “phase side by side” type during steel deformation. Methods. Destruction of various types heterophase inclusions is investigated during the deformation of samples from steels 08Ti, 08Al, 12MnSi, 08unk, 09Mn2Si, 08GSiAlTiV in the temperature range 20...1 200 °С. Samples of 08Ti and 08Al steels are subjected to tension, compression and bending, steel HB-57 − to tension and compression, steel 08unk, 08Cr, ATs45X ,ATs18XGT − to tension in vacuum at temperatures of 20...1 200 °С on experimental settings with special grips, which motion speed was 20 mm/min. Methods of investigation – petrography, X-ray microanalysis and optical microscopy were used. Results. It has been found that the diversity of phases composing the heterophase inclusions of the “phase side by side” type leads to their different behaviour under plastic deformation. The microcracks nitiation occurs along the internal interphase boundaries. Depending on the plasticity level of the phases composing the inclusion, these cracks can be brittle or ductile, which is also related to the effects of the deformation temperature. The features of microcracks initiation for different combinations of heterophase inclusions plastic and non-deformed phases of the “phase side by side” type are analysed. The interaction between heterophase inclusions of the “phase side by side” type and the steel matrix during deformation is discussed. Scientific novelty. The features of microcrack initiation related to heterophase inclusions of “phase side by side” type with different combination of brittle and plastic phases during steels deformation in a wide temperature range is determined. It was found that the microcracks initiation and spreading within inclusions “phase side by side” type occurs both in phases and along internal interphase boundaries. It is shown that the critical degrees of samples deformation, at which significant microcracks along the internal interphase boundaries occur, depend on the temperature and the inclusion phase. The critical degrees of samples deformation, upon reaching which significant microcracks occurred along the internal interphase boundaries, depended on the temperature and the nature of the “phase side by side” inclusions. The values of the critical degrees of deformation determine the level of cohesive strength of the internal interphase boundaries of the heterophase inclusions “phase side by side”. Practical significance. The use of obtained results will make it possible to develop technologies for producing steels with regulated types of heterophase non-metallic inclusions. This will substantially improve their technological and performance characteristics and prevent the various defects formation in the steel pressure treatment and the products operation.
36
Liu, Kai, Si Jin Wu, Xin Ya Gao e Lian Xiang Yang. "Simultaneous Measurement of In-Plane and Out-of-Plane Deformations Using Dual-Beam Spatial-Carrier Digital Speckle Pattern Interferometry". Applied Mechanics and Materials 782 (agosto 2015): 316–25. http://dx.doi.org/10.4028/www.scientific.net/amm.782.316.
Abstract (sommario):
Digital speckle pattern interferometry (DSPI) is an advanced technique for both in-plane and out-of-plane deformation measurements of diffuse surfaces in nanoscale. It has been widely used in aerospace engineering and other high-tech industries due to the advantages of non-contact, high-accuracy and full-field measurement. Traditionally, DSPI uses temporal phase shifting method to achieve precise deformation measurement, but it is only suitable for quasi-static deformation. Spatial-carrier method is another effective phase retrieval method used in DSPI and its validity has been verified in some DSPI setups. DSPI with spatial-carrier method enjoys the advantages of simple optical arrangement, easy operation, and above all, high-speed measurement of deformation. This paper introduces a dual-beam spatial-carrier digital speckle pattern interferometry system, with which in-plane and out-of-plane deformations can be measured simultaneously as well as quickly. In the optical setup, two lasers are employed to illuminate the measured object with different illumination angles, and two single-mode fibers server as carriers to transmit the reference beams. In-plane and out-of-plane deformations can be obtained by combining the phase maps of both channels. Theoretical discussion and experimental analysis are both presented.
37
Bassani, Paola, Marco Breda, Katya Brunelli, Istvan Mészáros, Francesca Passaretti, Michela Zanellato e Irene Calliari. "Characterization of a Cold-Rolled 2101 Lean Duplex Stainless Steel". Microscopy and Microanalysis 19, n. 4 (31 maggio 2013): 988–95. http://dx.doi.org/10.1017/s1431927613001426.
Abstract (sommario):
AbstractDuplex stainless steels (DSS) may be defined as a category of steels with a two-phase ferritic–austenitic microstructure, which combines good mechanical and corrosion properties. However, these steels can undergo significant microstructural modification as a consequence of either thermo-mechanical treatments (ferrite decomposition, which causes σ- and χ-phase formation and nitride precipitation) or plastic deformation at room temperature [austenite transformation into strain-induced martensite (SIM)]. These secondary phases noticeably affect the properties of DSS, and therefore are of huge industrial interest. In the present work, SIM formation was investigated in a 2101 lean DSS. The material was subjected to cold rolling at various degrees of deformation (from 10 to 80% thickness reduction) and the microstructure developed after plastic deformation was investigated by electron backscattered diffraction, X-ray diffraction measurements, and hardness and magnetic tests. It was observed that SIM formed as a consequence of deformations higher than ~20% and residual austenite was still observed at 80% of thickness reduction. Furthermore, a direct relationship was found between microstructure and magnetic properties.
38
Tsuzaki, Kaneaki, Andrey Belyakov e Yuuji Kimura. "Deformation Microstructures in a Two-Phase Stainless Steel during Large Strain Deformation". Materials Science Forum 503-504 (gennaio 2006): 305–10. http://dx.doi.org/10.4028/www.scientific.net/msf.503-504.305.
Abstract (sommario):
Deformation microstructures were studied in a two-phase (about 60% ferrite and 40% austenite) Fe – 27%Cr – 9%Ni stainless steel. Severe plastic working was carried out by rolling from 21.3×21.3 mm2 to 7.8×7.8 mm2 square bar followed by swaging from Ø7.0 to 0.6 mm rod at an ambient temperature, providing a total strain of 6.9. After a rapid increase in the hardness at an early deformation, the rate of the strain hardening gradually decreased to almost zero at large strains above 4. In other words, the hardness approached a saturation level, leading to an apparent steadystate deformation behaviour during cold working. The severe deformation resulted in the evolution of highly elongated (sub)grains aligned along the rolling/swaging axis with the final transverse (sub)grain size of about 0.1 μm and the fraction of high-angle (sub)boundaries above 60%. However, the kinetics of microstructure evolution in the two phases was different. In the ferrite phase, the transverse size of deformation (sub)grains gradually decreased during the processing and approached 0.1 μm at strains of about 6.0, while the transverse size of the austenite (sub)grains rapidly reduced to its final value of 0.1 μm after a relatively low strain about 1.0.
39
Andreyachshenko, V., e A. Toleuova. "On the influence of iron and silicon content on the phase composition of the Al-Fe-Si system". Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources 332, n. 1 (3 maggio 2024): 98–107. http://dx.doi.org/10.31643/2025/6445.09.
Abstract (sommario):
Increasing interest in intermetallic phases of the Al-Fe-Si system is associated with their high specific strength, corrosion and wear resistance, as well as the low cost of their production. To exhibit the most successful combination of properties, it is necessary to impart a specific compact morphology to the precipitated intermetallic phases. It is important to create an alloy with a composition capable of accepting plastic deformation. The purpose of the work is to develop the composition of an Al-Fe-Si system alloy capable of withstanding plastic deformation and determining the corresponding deformation interval. Based on computer modeling, an alloy composition capable of accepting plastic deformation was developed and the corresponding deformation interval was determined. The simulation was carried out in the ThermoCalc software package, TCAL8 database. It has been revealed that alloys with a high content of both silicon and iron are not characterized by the formation of a single-phase region, however, with a certain combination of alloy components, it is possible to achieve a quasi-single-phase structure, when the content of one phase is observed to be more than 90%. The solidus temperatures for different alloy compositions and the boundary conditions for the existence of phases have been determined. The α phase is present in the system from a temperature of 770°C up to a temperature of 446°C. In composition, it is found in the range from 5 to 35% iron with an amount of silicon of 10% and from 0 to 15% silicon with an iron content of 30%. The maximum amount of α phase was obtained for the Al60-65 alloy; Fe30-32; and Si5-10%, deformation temperature range is 600-450°C. Deformation in this region will ensure processing in a quasi-single-phase region without melting.
40
Fan, Caihe, Ling Ou, Jianjun Yang e Xihong Chen. "Nano-Precipitated Phase and Evolution of Al-Cu-Mg Alloy Subjected to Rapid Cold Stamping". Nanoscience and Nanotechnology Letters 11, n. 9 (1 settembre 2019): 1318–26. http://dx.doi.org/10.1166/nnl.2019.3003.
Abstract (sommario):
High-resolution transmission electron microscopy, energy dispersive spectroscopy, and hardness test were used to study the nano-precipitates and evolution of nano-precipitation of the sprayformed fine-grained Al-Cu-Mg alloy during rapid cold stamping deformation. Results show that the elongated S-phase and the acicular ' phase of the Al-Cu-Mg alloy after three passes of cold stamping of rapid cold-shock deformation undergoes re-dissolution, and a large number of the fine granular balance phases are precipitated after four passes of rapid cold-stamping deformation. The main mechanism of low-temperature re-dissolution of S' phase and ' phase in Al-Cu-Mg alloy induced by rapid cold stamping deformation is the precipitation phase fracture, grain boundary diffusion, and vacancy diffusion. The change in the hardness of the alloy during rapid cold stamping deformation is affected by the combination of phase-resolving softening, work hardening, and reprecipitation strengthening and increases at three stages. The hardness increases from 55 HB to 125 HB, which is increased by 127%.
41
Chen, Mingsong, Quan Chen, Yumin Lou, Yongcheng Lin, Hongbin Li, Guanqiang Wang e Hongwei Cai. "Effect of Deformation Parameters of an Initial Aged GH4169 Superalloy on Its Microstructural Evolution during a New Two-Stage Annealing". Materials 15, n. 16 (11 agosto 2022): 5508. http://dx.doi.org/10.3390/ma15165508.
Abstract (sommario):
This study aims to explore the effect of deformation parameters on microstructure evolution during the new two-stage annealing method composed of an aging treatment (AT) and a cooling recrystallization annealing treatment (CRT). Firstly, the hot compressive tests with diverse deformation parameters were finished for an initial aged deformed GH4169 superalloy. Then, the same two-stage annealing method was designed and carried out for the deformed samples. The results show that the deformation parameters mainly affect the grain microstructure during CRT by influencing the content, distribution and morphology of the δ phase after deformation. The reason for this is that there is an equilibrium of the content of the δ phase and Nb atom. When the deformation temperature is high, the complete dissolution behavior of the δ phase nuclei promotes the dispersion distribution of the δ phase with rodlike and needle-like shapes during AT. Thus, the fine and heterogeneous microstructure is obtained after annealing because the recrystallization nucleation is enhanced in those dispersed δ phases during CRT. However, when the retained content of δ phase nuclei is high after deformation, the clusters of intragranular δ phases will form during AT, resulting in the pinning of the motion for dislocation. The elimination of the mixed grain microstructure is slowed down due to the low static recrystallization (SRX) nucleation rate within the deformed grain.
42
Bursnall, J. T., A. D. Leclair, D. E. Moser e J. A. Percival. "Structural correlation within the Kapuskasing uplift". Canadian Journal of Earth Sciences 31, n. 7 (1 luglio 1994): 1081–95. http://dx.doi.org/10.1139/e94-097.
Abstract (sommario):
Comparison of progressive deformation and metamorphic history within and between the tectonic domains of the Kapuskasing uplift indicates significant variation in age and style of deformation across this large segment of the central Superior Province; multiple stages of tonalite and granitoid intrusion, melt generation, polyphase diachronous deformation, and likely rapid deep burial of supracrustal rocks collectively produced the complex character of this example of Archean mid to deep crust. At least four Archean deformation phases are recognized, although not all are of regional extent. Dated structural chronology suggests that the locus of the earliest recorded deformations migrated to deeper crustal levels with time. Pre-2680 Ma deformation (local D1–D2) within high-level tonalites is correlated with deformation in the Michipicoten supracrustal belt. The apparent earliest deformational fabrics at deeper crustal levels in the granulite terrane of the Kapuskasing structural zone occurred between 2660 and 2640 Ma. Archean third and fourth phase deformation phases (~ 2667 to ~ 2629 Ma) are present at mid-crustal and deeper levels and deform post-2667 Ma metaconglomerate; these resulted in large-scale folding and subhorizontal ductile shear zones, which seem to represent an important transitional zone that separated a passive upper crust from continued ductile strain at deeper levels.Subsequent uplift of the high-grade rocks was accomplished in multiple stages, initiated prior to 2.45 Ga and likely culminated around 1.9 Ga, although continued movement occurred as late as 1.14 Ga. The Ivanhoe Lake fault zone, along which much of the uplift must have occurred, exhibits some evidence of ductile deep-thrust-related fabrics, but most of the observed structures are brittle to brittle–ductile and steeply inclined. A broad zone of pervasive cataclasis and brittle–ductile shear zones is a characteristic feature of the fault zone throughout its length, and both dextral and sinistral offset are locally present. Clear ground evidence for major transcurrent or thrust displacements, however, has not been recognized.
43
Hu, Xin, Yanzhou Ji, Lei Chen, Ricardo A. Lebensohn, Long-Qing Chen e Xiangyang Cui. "Spectral phase-field model of deformation twinning and plastic deformation". International Journal of Plasticity 143 (agosto 2021): 103019. http://dx.doi.org/10.1016/j.ijplas.2021.103019.
44
Yang, Yongjie, Huiqiang Duan, Luyi Xing, Shan Ning e Jiakun Lv. "Fatigue Characteristics of Limestone under Triaxial Compression with Cyclic Loading". Advances in Civil Engineering 2018 (2 settembre 2018): 1–12. http://dx.doi.org/10.1155/2018/8681529.
Abstract (sommario):
This paper presents an experimental investigation of the fatigue properties of limestone subjected to triaxial compression with axial cyclic loading. Tests were conducted on intact limestone samples with a loading frequency of 0.5 Hz and a confining pressure of 10 MPa. The test results show the following five points. (1) Under triaxial conditions, the axial and circumferential deformations at the failure point induced by cyclic loading are slightly larger than the corresponding deformations at the peak stress achieved by conventional compression tests. (2) The first level cyclic loading process has a strong influence on rock deformation in the primary phase during subsequent level cyclic loading. A smaller difference in stress amplitude between the two loading stress levels leads to less deformation during the latter. (3) Circumferential and volumetric changes are more sensitive to fatigue failure in terms of deformation and strain rate than axial changes. (4) The three phases of dissipated energy evolution are consistent with a sample’s deformation such that the energy dissipation characteristics reflect the fatigue damage evolution process. (5) A new damage formula is proposed that can concisely describe a rock’s zero-cycle damage and damage evolution.
45
Wei, Chenshuang, Sai Tang, Yi Kong, Xiong Shuai, Hong Mao e Yong Du. "Atomic-Scale Insights into the Deformation Mechanism of the Microstructures in Precipitation-Strengthening Alloys". Materials 16, n. 5 (23 febbraio 2023): 1841. http://dx.doi.org/10.3390/ma16051841.
Abstract (sommario):
Clarifying the deformation behaviors of microstructures could greatly help us understand the precipitation-strengthening mechanism in alloys. However, it is still a formidable challenge to study the slow plastic deformation of alloys at the atomic scale. In this work, the phase-field crystal method was used to investigate the interactions between precipitates, grain boundary, and dislocation during the deformation processes at different degrees of lattice misfits and strain rates. The results demonstrate that the pinning effect of precipitates becomes increasingly strong with the increase of lattice misfit at relatively slow deformation with a strain rate of 10−4. The cut regimen prevails under the interaction between coherent precipitates and dislocations. In the case of a large lattice misfit of 19.3%, the dislocations tend to move toward the incoherent phase interface and are absorbed. The deformation behavior of the precipitate-matrix phase interface was also investigated. Collaborative deformation is observed in coherent and semi-coherent interfaces, while incoherent precipitate deforms independently of the matrix grains. The faster deformations (strain rate is 10−2) with different lattice misfits all are characterized by the generation of a large number of dislocations and vacancies. The results contribute to important insights into the fundamental issue about how the microstructures of precipitation-strengthening alloys deform collaboratively or independently under different lattice misfits and deformation rates.
46
Marzuki, Marzuki, Zul Ikram e Vira Friska. "Deformation Analysis of 2012 Mw8.6 Indian Ocean Earthquake Based on GPS Data in Preseismic, Coseismic, and Postseismic Phases". Jurnal Penelitian Pendidikan IPA 8, n. 6 (28 dicembre 2022): 2785–92. http://dx.doi.org/10.29303/jppipa.v8i6.2419.
Abstract (sommario):
The earthquake was one of the biggest natural disasters in Sumatra and dramatically affected this region and the surrounding area. Determination of surface deformation due to the earthquake is essential for disaster mitigation. The Global Navigation Satellite System (GNSS) is a commonly used method for determining surface deformation due to earthquakes. This study analyzes surface deformation during the preseismic, coseismic, and postseismic phases due to the 2012 Mw8.6 Indian Ocean earthquake. The study used Global Positioning System (GPS) data from the Sumatran GPS Array (SuGAr) network. The most significant horizontal deformation was observed at the LEWK station, which was 280.554 mm towards the northeast and experienced a subsidence of 40.830 mm in vertical deformation. Horizontal deformation is still felt by 22.453 mm to the northeast and vertical deformation of 8.810 mm (uplift) at stations that are farther (580 km) from the earthquake's epicenter. However, in the observation period of 60 days (postseismic phase), stations closer to the epicenter are still experiencing a postseismic phase. In contrast, stations far from the epicenter show that the postseismic phase is almost complete. In the preseismic phase, all stations experience almost the same horizontal deformation, ranging from 2.210 mm-3.639 mm, but with a different direction of movement, which may be caused by previous intense earthquake activity, which is still releasing energy (postseismic phase). On the other hand, the vertical deformation during the preseismic phase generally experiences an uplift except at the LEWK station. The results of this study can be additional information for earthquake mitigation in the Sumatra region
47
Zhou, Bijin, Jie Wang, Hailong Jia, Ting Hao, Zhenwu Ma, Leyun Wang e Xiaoqin Zeng. "Deformation Behavior of β Phase in a WE54 Magnesium Alloy". Materials 16, n. 4 (11 febbraio 2023): 1513. http://dx.doi.org/10.3390/ma16041513.
Abstract (sommario):
Second phases play a significant role in the development of high-performance magnesium alloys with rare earth elements. Here, in situ tensile tests combined with synchrotron radiation were carried out to investigate the deformation behavior of β phases in a WE (Mg–Y–Gd–Nd) alloy. By lattice strain analysis, it was found that micro load continuously transferred from the soft α-Mg matrix to the hard β phases during the whole plastic deformation, while this behavior was much more obvious at the beginning of deformation. Based on diffraction peak broadening, Williamson–Hall (W–H) plotting was used to study the microstrain of β phases. The results showed that the microstrain of β phases increased rapidly within 4% plastic strain and reached the maximum at plastic strain of ~6.5%. Since the β phases acted as hard phases, the microstrain was considered as a sign of the stress concentration near phase interfaces. It was also suggested that the effective release of local stress concentration at the β/α-Mg interface benefited the ductility of the WE alloy by the plastic deformation of β phases and phase interface sliding.
48
Vasconcelos, Bruno Rodrigo, Amarildo Salina Ruiz e João Batista de Matos. "Polyphase deformation and metamorphism of the Cuiabá group in the Poconé region (MT), Paraguay Fold and Thrust Belt: kinematic and tectonic implications". Brazilian Journal of Geology 45, n. 1 (marzo 2015): 51–63. http://dx.doi.org/10.1590/23174889201500010004.
Abstract (sommario):
Several deformation models have been proposed for the Paraguay Belt, which primarily differ in the number of phases of deformation, direction of vergence and tectonic style. Structural features presented in this work indicate that the tectonics was dominated by low dip thrust sheets in an initial phase, followed by two progressive deformation phases. The first phase of deformation is characterized by a slate cleavage and axial plane of isoclinal recumbent folds with a NE axial direction, with a recrystallization of the minerals in the greenschist facies associated with horizontal shear zones with a top-to-the-SE sense of movement. The second stage shows vergence towards the NW, characterized by crenulation cleavage axial plane to F2 open folds over S0 and S1, locally associated with reverse faults. The third phase of deformation is characterized by subvertical faults and fractures with a NW direction showing sinistral movement, which are commonly filled by quartz veins. The collection of tectonic structures and metamorphic paragenesis described indicate that the most intense deformation at the deeper crustal level, greenschistfacies, occurred during F1, which accommodated significant crustal shortening through isoclinal recumbent folds and shear zones with low dip angles and hangwall movement to the SE, in a thin-skinned tectonic regime. The F2 deformation phase was less intense and had a brittle to ductile behavior that accommodated a slight shortening through normal open subvertical folds, and reverse faults developed in shallower crustal level, with vergence towards the Amazonian Craton. The third phase was less pervasive, and the shortening was accommodated by relief subvertical sinistral faults.
49
Gao, Yushe, Xiangyi Xue, Huixian Gao, Wenzhong Luo, Kaixuan Wang, Shaoqiang Li, Xianghong Liu e Yuxuan Du. "Investigation of High-Temperature Constitutive Behavior of Ti555211 Titanium Alloy Subjected to Plastic Deformation in the Different Phase Regions". Metals 12, n. 10 (21 settembre 2022): 1562. http://dx.doi.org/10.3390/met12101562.
Abstract (sommario):
Ti555211 titanium alloy is subjected to plastic deformation in the dual-phase (α + β phase) zone and single-phase (β phase) zone at various deformation temperatures and strain rates. High-temperature constitutive equations of the alloy in the dual-phase zone and single-phase zone are established in order to describe deformation behavior of the alloy in the different phase zones. By comparing the constitutive equation of the alloy in the dual-phase zone with that of the alloy in the single-phase zone, the deformation activation energy of the former was found to be higher than that of the latter. It is obvious that the deformation activation energy of α phase is obviously greater than that of β phase. Furthermore, the microstructural evolution of the alloy is different in the dual-phase zone and single-phase zone. When the alloy was subjected to plastic deformation in the dual-phase zone, the size of the grains in the β phase increased with the decreasing strain rate. When the alloy was subjected to plastic deformation in the single-phase zone, the size of the grains in the β phase considerably increased with the increasing deformation temperature. In particular, in the microstructures of the alloy subjected to plastic deformation in the single-phase region, the elongated grains can be observed at higher strain rates. Furthermore, it is more difficult for the alloy to induce plastic deformation in the dual-phase region than in the single-phase region.
50
Chen, Yongqian, Songhua Yan e Jianya Gong. "Deformation Estimation Using Beidou GEO-Satellite-Based Reflectometry". Remote Sensing 13, n. 16 (19 agosto 2021): 3285. http://dx.doi.org/10.3390/rs13163285.
Abstract (sommario):
Deformation monitoring has been brought to the fore and extensively studied in recent years. Global Navigation Satellite System Reflectometry (GNSS-R) techniques have so far been developed in deformation estimation applications, which however, are subject to the influence of mobile satellites. Rather than compensating for the path delay variations caused by mobile satellites, adopting Beidou geostationary Earth orbit (GEO) satellites as transmitters directly eliminates the satellite-motion-induced phase error and thus provides access to stable phase information. This paper presents a novel deformation monitoring concept based on GNSS-R utilizing Beidou GEO satellites. The geometrical properties of the GEO-based bistatic GNSS radar system are explored to build a theoretical connection between deformation quantity and the echo carrier phases. A deformation retrieval algorithm is proposed based on the supporting software receiver, thus allowing echo carrier phases to be extracted and utilized in deformation retrieval. Two field validation experiments are conducted by constructing passive bistatic radars with reflecting plates and ground receiver. Utilizing the proposed algorithm, the experimental results suggested that the GEO-based GNSS reflectometry can achieve deformation estimations with an accuracy of around 1 cm when the extracted phases does not exceed one complete cycle, while better than 3 cm when considering the correct integer number of phase cycles. Consequently, based on the passive bistatic radar system, the potential of achieving continuous, low-cost deformation monitoring makes this novel technique noteworthy.