Analyses of Dislocation Effects on Plastic Deformation

Mohamadnejad, Sedigheh; Basti, Ali; Ansari, R.

doi:10.1007/s42493-020-00037-2

Cited by 14 publications

(7 citation statements)

References 211 publications

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“…The previous results ( Figure 3 ) show that the decrease in transformation stress in a bicrystal Cu-Al-Mn SMA under a strain-controlled cyclic compression–unloading test was affected by the accumulation of residual strain. These macroscopic residual strains are mainly a result of dislocation slips in the austenite phase [ 19 , 20 , 21 , 22 , 23 , 24 ] and accumulated residual martensite phase owing to an incomplete reverse MT [ 19 , 25 , 26 ]. These dislocation slips, which can be triggered separately during forward and reverse MTs [ 27 ], are fostered by localized stress fields between austenite–martensite interfaces during forward and reverse MTs [ 20 , 28 , 29 , 30 ].…”

Section: Discussionmentioning

confidence: 99%

On the Decrease in Transformation Stress in a Bicrystal Cu-Al-Mn Shape-Memory Alloy during Cyclic Compressive Deformation

Chen

2021

Materials

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The evolution of the inhomogeneous distribution of the transformation stress (σs) and strain fields with an increasing number of cycles in two differently orientated grains is investigated for the first time using a combined technique of digital image correlation and data-driven identification. The theoretical transformation strains (εT) of these two grains with crystal orientations [5 3 26]β and [6 5 11]β along the loading direction are 10.1% and 7.1%, respectively. The grain with lower εT has a higher σs initially and a faster decrease in σs compared with the grain with higher εT. The results show that the grains with higher σs might trigger more dislocations during the martensite transformation, and thus result in greater residual strain and a larger decrease in σs during subsequent cycles. Grain boundary kinking in bicrystal induces an additional decrease in transformation stress. We conclude that a grain with crystal orientation that has high transformation strain and low transformation stress (with respect to loading direction) will exhibit stable transformation stress, and thus lead to higher functional performance in Cu-based shape memory alloys.

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Section: Discussionmentioning

confidence: 99%

On the Decrease in Transformation Stress in a Bicrystal Cu-Al-Mn Shape-Memory Alloy during Cyclic Compressive Deformation

Chen

2021

Materials

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“…The combination of Equations ( 7) and ( 8) are commonly used to describe stress curves both in basic [21] and empirical work [22,23]. A list of other similar papers can be found in [24].…”

Section: Dislocation Modelmentioning

confidence: 99%

“…where σ disl is the strength contribution from the dislocations, σ y is the yield strength, α = 0.19, a theoretically derived constant [15,28], and G is the shear modulus. The strain dependence of the strength is obtained by combining Equations ( 23) and (24).…”

Section: Basic Modelmentioning

confidence: 99%

Basic Modelling of General Strength and Creep Properties of Alloys

Sandström

2023

Crystals

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There are excellent methods for modelling physical and elastic properties, for example, those based on ab initio atomistic procedures. For mechanical properties that are controlled by the motion of the dislocations, such methods have not been available in the past. One has been forced to resort to fitting the experimental data with empirical methods by involving a number of adjustable parameters. However, in recent years, methods based on physical principles have been developed for a number of mechanical properties. These methods can predict properties accurately without the use of fitting parameters. A review of such methods will be given, for example, for the modelling of creep deformation in metallic materials. It will be demonstrated that some properties can be described over a wide range of temperatures and strain rates. The advantage of these new methods is that they can be used for prediction, identification of mechanisms and extrapolation of results for new conditions.

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“…Therefore, analyzing these dynamics lies at the core of understanding various plastic processes. In most cases, however, direct observation of the development of dislocation complexes is impossible [2,3]. One alternative to direct observation is to run molecular dynamics (MD) simulations to study the plastic response of metals.…”

Section: Introductionmentioning

confidence: 99%

Detection of dislocation motion in atomistic simulations of nanocrystalline materials

Dimanstein Firman,

Engelberg,

Ashkenazy

2024

Modelling Simul. Mater. Sci. Eng.

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A method for identifying dislocation motion in atomistic simulations is presented. While identifyingstatic and moving dislocations within a single crystal or a combination of such is well established,the method described here is tailored to identify dislocation motion by correlating the displacementsof individual atoms. This facilitates the identification of dislocation motion in complex structuralarrangements, and allows the specific contribution to plastic deformation, due to dislocation motion,to be separated from that of other mechanisms. The method is applied to test cases in crystals andgrain boundaries, in which irradiation-induced creep was induced. It is shown that the methodsingles out the moving dislocations from among the dislocation forest at grain boundaries, thusidentifying the specific reactions driving the distortion at any given time. This enables the studyof dislocation processes in the presence of realistic obstacles, and the study of the effects of microstructureon dislocation mobility. As an example of such a study, the method is applied to ruleout intragranular slip, and to estimate the contribution of dislocation motion to strain, in a NCundergoing irradiation-induced creep.

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Analyses of Dislocation Effects on Plastic Deformation

Cited by 14 publications

References 211 publications

On the Decrease in Transformation Stress in a Bicrystal Cu-Al-Mn Shape-Memory Alloy during Cyclic Compressive Deformation

On the Decrease in Transformation Stress in a Bicrystal Cu-Al-Mn Shape-Memory Alloy during Cyclic Compressive Deformation

Basic Modelling of General Strength and Creep Properties of Alloys

Detection of dislocation motion in atomistic simulations of nanocrystalline materials

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