Discrete Dislocation Research Articles

A discrete dislocation dynamics study of precipitate bypass mechanisms in nickel-based superalloys

Order strengthening in nickel-based superalloys is associated with the extra stress required for dislocations to bypass the γ′ precipitates distributed in the γ matrix. Depending on the operating conditions and microstructure, a rich variety of bypass mechanism has been identified, with various shearing and Orowan looping processes gradually giving way to climb bypass as the operating conditions change from the low/intermediate temperatures and high stress regime, to the high temperature and low stress regime. When anti phase boundary (APB) shearing and Orowan looping mechanisms operate, the classical picture is that, at for a given volume fraction, the bypass mechanism changes from shearing to looping with increased particle size and within a broad coexistence size window. Another possibility, which is supported by indirect experimental evidence, is that a third “hybrid” transition mechanism may operate. In this paper we use discrete dislocation dynamics (DDD) simulations to study dislocation bypass mechanisms in Ni-based superalloys. We develop a new method to compute generalized stacking fault forces in DDD simulations, based on a concept borrowed from complex analysis and known as the winding number of a closed curve about a point. We use this method to study the mechanisms of bypass of a square lattice of spherical γ′ precipitates by a/2〈110〉{111} edge dislocations, as a function of the precipitates volume fraction and size. We show that not only the hybrid mechanism is possible, but also that it operates as the transition mechanism between the shearing and looping regimes over a wide range of precipitates volume fraction and radii. Based on our simulation results, we propose a simple model for the strength of this mechanism. We also consider the effects of a γ/γ′ lattice misfit on the bypass mechanisms, which we approximate by an additional precipitate stress computed according to Eshelby’s inclusion theory. We show that in the shearing and hybrid looping-shearing regimes, a lattice misfit generally results in an increased bypass stress. For sufficiently high lattice misfit, the critical bypass configuration in attractive dislocation-precipitates interactions changes dramatically, and the bypass stress is controlled by the pinning of the trailing dislocation on the exit side of the precipitates, similar to what has been reported in the high-temperature creep literature.

Influence of near-surface dislocation cellular structure on Bauschinger effect

Long range internal stress (LRIS) based mechanism and non-LRIS explanation regarding Bauschinger effect are in debate. LRIS is originated from dislocation pile-up and/or cell generated by the pre-loading, therefore dislocation structure characterization of pre-strained sample is critical to clarify this academic dispute. Dislocation structures in surface and bulk regions of pure Ni deformed to a low strain level are characterized and compared in this work. Discrete dislocations are presented as expected in the bulk region of Ni, however, the main feature in its surface region is dislocation cell with average size of 1.2 μm. The result suggests that the promoted development of dislocation cellular pattern in near-surface region plays a critical role in the Bauschinger effect. It helps to clarify the mechanisms of Bauschinger effect and reconfirm the LRIS based mechanism.

Avalanche correlations and stress-strain curves in discrete dislocation plasticity

The sequence of deformation bursts during plastic deformation exhibits scale-free features. In addition to the burst or avalanche sizes and the rate of avalanches the process is characterized by correlations in the series which become manifest in the resulting shape of the stress-strain curve. We analyze such features of plastic deformation with two-dimensional and three-dimensional simulations of discrete dislocation dynamics models and we show that only with severe plastic deformation the ensuing memory effects become negligible. The role of past deformation history and dislocation pinning by disorder are studied. In general, the correlations have the effect of reducing the scatter of the individual stress-strain curves around the mean one.

Key role of interaction between dislocations and hydrogen-vacancy complexes in hydrogen embrittlement of aluminum: discrete dislocation plasticity analysis

With the development of experimental techniques and characterization methods at the microscopic scale, a high concentration of hydrogen-induced vacancies and their clusters have been detected in a large variety of metals and alloys charged with hydrogen, which is supposed to play an important role in hydrogen-induced fracture process. In hydrogen environment, vacancies and their clusters can trap a certain number of H atoms to form vacancy-H complexes or clusters. To investigate the role of hydrogen-induced vacancies and their clusters in brittle-like failure in hydrogen environment, multi-scale modelling was performed in this work, with a particular attention on the interaction between dislocations and vacancy-H complexes. Firstly, the H-enhanced vacancy formation due to H-induced reduction in vacancy formation energy in Al was modelled by first principles calculations, and a hydrogen-influenced vacancy concentration model was proposed. Then, to capture the interaction between gliding edge dislocations and vacancy-H complexes and clusters, atomistic simulations were performed, and a mesoscale model quantitatively describing the pinning effect of vacancy-H complexes and clusters on the gliding edge dislocations was obtained. Finally, these quantitative models were introduced into a newly developed XFEM-based discrete dislocation plasticity scheme. With this scheme, mode-I crack propagation was simulated, where dislocation emission from crack-tip, dislocation evolution and cohesive crack propagation were considered, with a particular attention to the key role of the hydrogen-influenced dislocation evolution in the brittle-like failure of the H-charged metals. Based on these multi-scale simulations, a pinning effect of H-enhanced vacancies and vacancy-H complexes on edge dislocations was identified, which was proposed to be responsible for the brittle-like failure of Al in hydrogen environment. This pinning effect presents a good agreement with the hydrogen-restricted dislocation mobility observed in in situ fracture experiments.

Advances in formation mechanisms and multiscale simulations of adiabatic shear bands in metallic materials

<p indent=0mm>Adiabatic shear bands (ASBs) become an important failure mechanism when the ductile metallic materials are loaded under the dynamic impact. This thermoplastic instability behavior occurring in such a narrow band under the coupling actions of force and thermal effect easily causes a rapid propagation of crack inside the ASB or along its boundary, subsequently leading to a sudden failure. The extremely small scale of adiabatic shear bands in space and time has brought great challenges to experimental investigations. For this reason, scholars have not obtained a comprehensive understanding of this unique mechanical behavior, but a lot of research work has already been done and many breakthroughs have been made in this research field. In the experimental studies, the applications of high-speed and high-resolution testing techniques make people observe the whole process of initiation and propagation of the ASBs more clearly, and further recognize the role of different influencing factors in the emergence of ASBs, more specifically, the causal relationship between the adiabatic temperature rising and plastic localization. Based on a large number of experimental results, scholars have summarized a variety of mechanical explanations in recent years to reveal the formation mechanism of adiabatic shear instability behavior. Moreover, in the aspect of numerical analysis, the scholars have already put forward many kinds of modelling and simulation methods to help discern the formation process of ASB. In addition to the modelling method at a macro scale, multiscale simulation methods consider different kinds of microscopic mechanisms in their constitutive relations. As such, the influences of different microscopic variables on the dynamic mechanical behavior can be analyzed independently via multiscale simulations, which can greatly promote the comprehension of formation mechanisms of adiabatic shear bands. In this review, the latest investigation advances on adiabatic shear instability behavior of the research group from impact dynamics and engineering application laboratory in Northwestern Polytechnical University, as well as a number of published results of other scholars, focusing on the formation mechanisms of ASBs in the metallic materials with different microscopic characteristics, are summarized. Firstly, the most classical thermal softening theory is discussed, and the latest measurement results revisiting the causal relationship between adiabatic temperature rise and localized deformation are reviewed. Then we briefly introduce some other softening mechanisms proposed based on the microstructure characteristics of metallic materials, including the geometric softening theory and dynamic recrystallization softening mechanism. Based on these above instability mechanisms, many simulation models are constructed to reproduce the formation process of ASBs. Therefore, we also systematically elaborate on the simulation studies on adiabatic shear instability behavior via multiscale simulation methods and track their respective progress. Besides the traditional modelling and finite element method at the macro scale, more simulations carried out at the meso/micro scales to reveal the physical essence of this behavior in recent years are stated, such as the crystal plasticity finite element method, phase filed simulation, discrete dislocation dynamics method and even atomistic simulations. Finally, we discuss the problems existing in this research field and future research focuses for the adiabatic shearing localizations.

On the microstructure and tensile properties of Inconel 718 alloy fabricated by selective laser melting and conventional casting

In this work, we investigated the microstructure and tensile properties of Inconel 718 alloy processed by selective laser melting (SLM) and conventional casting technique using multiscale characterization methods. Results indicated that a columnar grain structure containing cellular structure units with submicron size was the major feature in the as-printed Inconel 718 alloy. At the cellular structure boundaries, the high-density dislocation tangles, segregation of Nb/Mo atoms and nano-sized Laves phases were found. Meanwhile, we also observed dislocation pile-ups and stacking faults in the interior of the cellular structure. In contrast, in the as-cast Inconel 718 alloy, both the grains and Laves phases were much coarser. Discrete dislocations, dislocation tangles and [Formula: see text]” precipitates were locally observed in the grains. Tensile results showed the as-printed Inconel 718 alloy had a higher strength and a lower elongation in comparison with those in the as-cast alloy. Based on the experimental results, the formation mechanism of the cellular structure was discussed.

DISCRETE DISLOCATION DYNAMICS SIMULATIONS FOR COMPRESSION OF PARTICLE REINFORCED COMPOSITES

Particle reinforced copper matrix composites have high strength, elastic modulus, excellent electrical and thermal conductivity and wear resistance, they are widely used in aerospace, rail transit, equipment manufacturing and other fields. In particle reinforced composites, the dislocation movement is prevented by small dispersed particles in the alloy, thus effectively improving the mechanical properties of metallic materials and enhancing their service safety. In this paper, the three-dimensional discrete dislocation dynamics (3D-DDD) method was used to simulate the compression of particles reinforced copper matrix composites micro-pillar. The influence of the dislocation-precipitate interaction on the mechanical response of the material was analyzed to reveal the microscopic mechanism of the precipitation strengthening. In this study, the precipitate was regarded as a spherical particle with an impenetrable surface. The dislocation bypass mechanism was used to simulate the interaction between the precipitates and the dislocations. By changing the relative distance of dislocation slip plane against the center of spherical particle, it is found that when the distance is zero, the yield strength and the subsequent strain hardening rate are the highest. As the slip plane is far away from the center of spherical particle, the yield strength and the strain hardening rate decreases. The study also found that the higher the Schmid factor, the lower the yield strength and the lower strain hardening rate. In the simulation of multiple dislocations, it was found that the reaction of dislocations in same slip planes and the interaction of dislocations in different slip systems may be responsible for the reduction of the yield strength and the strain hardening rate.

Dislocation dynamics modelling of the creep behaviour of particle-strengthened materials.

Plastic deformation in crystalline materials occurs through dislocation slip and strengthening is achieved with obstacles that hinder the motion of dislocations. At relatively low temperatures, dislocations bypass the particles by Orowan looping, particle shearing, cross-slip or a combination of these mechanisms. At elevated temperatures, atomic diffusivity becomes appreciable, so that dislocations can bypass the particles by climb processes. Climb plays a crucial role in the long-term durability or creep resistance of many structural materials, particularly under extreme conditions of load, temperature and radiation. Here we systematically examine dislocation-particle interaction mechanisms. The analysis is based on three-dimensional discrete dislocation dynamics simulations incorporating impenetrable particles, elastic interactions, dislocation self-climb, cross-slip and glide. The core diffusion dominated dislocation self-climb process is modelled based on a variational principle for the evolution of microstructures, and is coupled with dislocation glide and cross-slip by an adaptive time-stepping scheme to bridge the time scale separation. The stress field caused by particles is implemented based on the particle–matrix mismatch. This model is helpful for understanding the fundamental particle bypass mechanisms and clarifying the effects of dislocation glide, climb and cross-slip on creep deformation.

Форма лінії дислокації в полі стохастичних зсувних напружень

The shape of the dislocation line in the stochastic shear stress field in the glide plane was studied using the method of discrete dislocation dynamics. Stochastic shear stresses can occur due to the distortion of the crystal lattice. Such distortion may exist, for example, in a solid solution. Different atoms in a solid solution induce atomic size misfit and elastic modulus misfit into crystal lattice. These misfits result in crystal lattice distortions which varies spatially. The distortions are the origin of internal stresses in the lattice. Such internal stress in certain location has stochastic value normally distributed. The particular case of such stresses is shear stress distribution in the glide plane. The special method was developed to model such stress distribution. The stochastic shear stress field results in movement of different segments of dislocation line to form its equilibrium shape. The important characteristic parameters of the equilibrium shape can be measured by numerical methods. This shape also includes a "long-wavelength" component that has a non-zero amplitude and was formed without thermal activation. The shape of the dislocation line determines to some extent the yield strength of the material. Thus, the study of dislocation line shape and modeling its formation in the field of stochastic shear stresses can help to determine the yield strength of multicomponent alloys, especially multi-principal element alloys. Keywords: dislocation, discrete dislocation dynamics, shear stresses.

Influence of θ′ Phase Cutting on Precipitate Hardening of Al–Cu Alloy during Prolonged Plastic Deformation: Molecular Dynamics and Continuum Modeling

We investigate the prolonged plastic deformation of aluminum containing θ′ phase with a multistage approach combining molecular dynamics (MD), continuum modeling (CM) and discrete dislocation dynamics (DDD). The time of performed MD calculations is sufficient for about a hundred dislocation–precipitate interactions. With this number of interactions, the inclusion of θ′ is not only cut, but also scattered into individual copper atoms in an aluminum matrix. Damage to the crystal structure of inclusion and activation of the cross-slip of dislocation segments cause a decrease in acting stresses in the MD system. The rate of this effect depends on θ′ diameter and occurs faster for small inclusions. The effect of decreasing the resistance of precipitate is further introduced into the dislocation–precipitate interaction CM by reducing the precipitate effective diameter with an increase in the number of interactions. A model of dislocation–precipitate interaction accounting for the softening of inclusions is further implemented into DDD. Dependences of flow stress in aluminum with θ′ phases on volume fraction and typical diameter of precipitates are obtained. Manifestation of inclusion softening is possible in such an alloy, which leads to the flow stress decrease during deformation. The range of volume fractions and typical diameters of θ′ phases corresponding to the possible decrease in flow stress is distinguished.

A discrete slip plane model for simulating heterogeneous plastic deformation in single crystals

In small-scale mechanical tests, such as micropillar compression tests, plastic deformation is often localized in narrow slip traces. These slip traces result from a few dislocation sources with relatively low nucleation stresses that are present in the material. In order to accurately simulate such small-scale experiments, the stochastics of the underlying dislocation network must be taken into account, which is usually done by performing discrete dislocation dynamics simulations. However, their high computational cost generally restricts these simulations to small and simple geometries and small applied displacements. Furthermore, effects of geometrical changes are usually neglected in the small strain formulation adopted. In this study, a discrete slip plane model for simulating small-scale experiments on single crystals is proposed, which takes the most important characteristics of dislocation plasticity for geometries in the micrometer range into account, i.e.the stochastics and physics of dislocation sources. In the model, the properties of all lattice planes are sampled from a probability density function. This results in a heterogeneous flow stress within a single crystal, unlike the uniform properties assumed in conventional crystal plasticity formulations. Moreover, the slip planes can be grouped together in bands via a weakest-link principle. The resulting equations are implemented in a standard crystal plasticity finite element model, using a finite deformation formulation. Within this setting, only the collective dislocation motion on glide planes is modeled, resulting in a significantly lower computational cost compared to frameworks in which the dynamics of individual dislocations are considered. This allows for simulating multiple realizations in 3D, up to large deformations. A small case study on micropillar compression tests is presented to illustrate the capabilities of the model.

A statistical model of irradiation hardening induced by non-periodic irradiation defects

Numerous efforts have been made to develop the irradiation hardening models, due to their important role in nuclear reactor design and service lifetime prediction. Most of the models are based on the dislocation line tension approximation, by assuming a periodic array of irradiation defects. The random distribution effect is also generally taken into account from a fully deterministic perspective, such as the well-known Bacon-Kocks-Scattergood model. Different from these previous studies, this work is aimed at developing a statistical irradiation hardening model by systematically coarsening the interaction mechanism between dislocation and non-periodic irradiation defects. The cumulative distribution function of the critical shear stress to overcome the irradiation defect barrier is obtained through the analytical derivation, and is lumped into a 2D Monte Carlo model to predict the mechanical response of irradiated material. The prediction results agree very well with three-dimensional discrete dislocation dynamics results and experimental data.

Study on hydrogen-affected interaction between dislocation and grain boundary by MD simulation

Hydrogen-affected dislocation motion and hydrogen-induced intergranular fracture play key roles in hydrogen embrittlement. The quantitative characterization of H-affected interaction between dislocation and grain boundary (GB) is of great significance to understand the underlying physics of hydrogen embrittlement, which is systematically studied here by hybrid Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. The structural features of GBs are depicted through the structural unit model (SUM) and grain boundary dislocation model (GBDM). The mechanisms of interactions between dislocation and H-free/H-segregated GB arethoroughly investigated and classified. For the cases without H segregation at GB, dislocation nucleation from GB and dislocation gliding on GB are the fundamental mechanisms governing the dislocation-GB interaction. In contrast, for the cases with H segregation, the dislocation-GB interaction mechanism is changed owing to H-inhibited GB dislocation emission, dislocation transmission across GB and dislocation gliding on GB. Due to dislocation pile-up promoted by H segregation, crack initiation is facilitated at the H-segregated GB. These results can provide essential information not only for understanding H-induced intergranular fracture but also for developing an up-scaled discrete dislocation dynamics (DDD) simulation framework.

Digital Representation and Quantification of Discrete Dislocation Structures

Dislocation networks and their evolution are known to control the mechanical properties of metal samples. However, the lack of computationally efficient and statistically rigorous descriptors for such defect systems has hindered the development and adoption of rational protocols for the optimal design of these material systems. This study presents a framework for the rigorous statistical quantification and low dimensional representation of dislocation networks using the formalism of 2-point spatial correlations (also called 2-point statistics) along with Principle Component Analysis (PCA). The usefulness of this basic framework for comparing and observing dislocation networks is exemplified and discussed with suitable examples.

Atomistic study and continuum modeling of solute strengthening in slip-CTB interaction

The slip-coherent twin boundary (CTB) interaction, which is one of the most important issues determining the strength and ductility of the face-centered cubic metals, is investigated by molecular dynamics (MD) simulations on a bi-crystal model of Ni with interstitial Cr and Fe in CTB. Two interaction types, i.e., absorption and transmission, are observed, with prominent dependence on both the type and fraction of the solute. The threshold shear stress triggering the slip-CTB reaction event is quantitatively evaluated, and based on the local lattice friction, a new interpretation of the mechanism for solute affected slip-CTB interaction is proposed. A continuum model for solution affected slip-CTB interaction is established from a discrete dislocation scenario, including modified formulations in terms of the balanced condition of stress acting on the leading partial and elevated lattice friction, where the solute effect is effectively accounted and incorporated. Accordingly, the criterion to determine the nature of slip-CTB reaction is proposed, yielding good prediction of the critical events observed in MD simulations. This paper provides critical understanding and predictive tools for solute affected slip-CTB interaction in Ni, and offers new insights into alloy and microstructure engineering of Ni based superalloys with improved mechanical properties.

Toward an In-Depth Material Model for Cermet Nuclear Thermal Rocket Fuel Elements

The development and qualification of nuclear thermal propulsion (NTP) fuel element technologies would be aided by an in-depth model of material response and failure modes at operating conditions. Integrated computational materials engineering techniques have the potential to provide such a model, as demonstrated here through three case studies focused on a tungsten–uranium mononitride (UN) cermet fuel. The first case focuses on the erosion of tungsten (also named wolfram), a nominal coating/cladding and fuel element matrix material, in hot hydrogen. Ab initio techniques are used to calculate erosion rates and thermal expansion at NTP operating conditions. The second focuses on the stability of UN fuels at high temperature and in the presence of hydrogen. Phase diagram techniques augmented with ab initio thermodynamic data reveal potential instabilities and decomposition pathways at high hydrogen concentrations. The third focuses on using microstructure information to predict high-temperature mechanical response and failure of tungsten. Combined finite element and discrete dislocation dynamics techniques provide mechanical properties in agreement with experimental methods. The integration of these techniques for an all-encompassing material model is discussed.

In-Situ SEM High Strain Rate Testing of Large Diameter Micropillars Followed by TEM and EBSD Postmortem Analysis

BackgroundDislocation dynamic simulations are intended as a tool to understand and predict the mechanical behavior of metallic materials, but its prediction has never been directly verified by experiments due to differences in specimen strain rate and size.ObjectiveIn this work, a comprehensive experimental framework is proposed to attempt direct comparison between experiments and discrete dislocation dynamics (DDD) modelling. MethodsBy integrating high-throughput sample fabrication and a customized testing apparatus, the sample size and strain rate typically employed in DDD simulations are explored experimentally. Constitutive properties such as stress-strain response are measured, and microstructural information is obtained from transmission electron microscopy (TEM) imaging, electron backscatter diffraction (EBSD), and TEM-based orientation mapping. ResultsMagnesium and copper were selected, as case studies, to demonstrate the newly developed experimental procedure. Measured stress-strain responses for Mg are consistent with those obtained with a miniaturized Hopkison bar experiments. By exploiting the validated workflow, the effect of strain rate on micropillar heterogeneous deformation and associated dislocation plasticity were revealed.ConclusionThe work establishes a methodology for the systematic study of not only metals but also other materials and structures at the microscale and high strain rates.

Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions

Ni-base superalloys show an intricate network of dislocations around γ′ precipitates during high-temperature low-to-intermediate stress creep. With an aim to understand the formation of this interfacial dislocation network on the surfaces of unsheared, cuboidal γ′ precipitates, we perform three-dimensional discrete dislocation dynamics simulations at constant stress in a model system containing superellipsoidal inclusions. The exponents of the superellipsoid are adjusted to fit the cuboidal shape of γ′. We use a fault-energy-based back-force model to describe interactions between dislocations and structurally inhomogeneous inclusions. The model incorporates climb of edge dislocation segments on non-glissile planes through a modified dislocation mobility law for face-centred cubic crystals. Athermal repulsive intersection cross-slip is considered for the screw segments. We systematically show the evolution of dislocation network as a function of applied stress, inter-particle spacing, and ratio of glide-to-climb mobility. We scale the simulation box and the inclusions by the same factor in order to keep the volume fraction of inclusions constant in all cases. Although the dislocation density increases with the increase in applied stress as well as inter-particle spacing, the onset of steady-state in all cases is marked by a constant mobile-to-immobile dislocation density (ρ m/ρ im) ratio. For the range of stresses and inter-particle spacings considered in this study, the steady-state ρ m/ρ im remains nearly the same. Our simulations indicate a power-law behaviour where the stress exponent n ≈ 4 suggests dislocation climb to be the rate-controlling mechanism. The simulated morphological features of the dislocation network formed on the surfaces of the inclusions at steady-state (e.g., hexagonal nets due to dislocation reactions) are similar to those observed experimentally in single-crystalline superalloys crept at high temperatures and low stresses. Moreover, we obtain a relationship between length scale associated with dislocation density and applied stress.

Slip-free multiplication and complexity of dislocation networks in FCC metals

During plastic deformation of crystalline solids, intricate networks of dislocation lines form and evolve. To capture dislocation density evolution, prominent theories of crystal plasticity assume that 1) multiplication is driven by slip in active slip systems and 2) pair-wise slip system interactions dominate network evolution. In this work, we analyze a massive database of over 100 discrete dislocation dynamics simulations (with cross-slip suppressed), and our findings bring both of these assumptions into question. We demonstrate that dislocation multiplication is commonly observed on slip systems with no applied stress and no plastic strain rate, a phenomenon we refer to as slip-free multiplication. We show that while the formation of glissile junctions provides one mechanism for slip-free multiplication, additional mechanisms which account for the influence of coplanar interactions are needed to fully explain the observations. Unlike glissile junction formation which results from a binary reaction between a pair of slip systems, these new multiplication mechanisms require higher order reactions that lead to complex network configurations. While these complex configurations have not been given much attention previously, they account for about 50% of the line intersections in our database.

3D discrete dislocation dynamic investigations of persistent slip band formation in FCC metals under cyclical deformation

The formation of persistent slip bands (PSBs) at early stages of fatigue plays an important role in fatigue damage. In order to get a better understanding of the physics involved at the dislocation scale, 3D discrete dislocation dynamic simulations are set up in the case of an isolated surface grain of Cu cyclically loaded in single slip. Simulations reveal the complex transformation process of the dislocation microstructure from a homogeneous distribution into an organized microstructure made of slip bands mainly composed of dislocation dipoles and prismatic loops. These slip bands are the embryo of the PSBs observed for large number of cycles. The localization mechanism evidenced by the simulations is well explained from a stress field analysis which highlights the role of cross-slip. A saturation regime is reached after a few cycles during which dislocation microstructure, dislocation densities and height of extrusions/intrusions remain unchanged. Furthermore, the linear relationship between the volume fraction of slip bands and the imposed plastic strain amplitude is retrieved by the simulations and the stability of the slip bands is verified by decreasing the plastic strain amplitude after the saturation regime is reached. Finally, when compared to AISI 316L stainless steel, Cu shows a tendency to build more bands with relatively larger thicknesses which is attributed to the differences in the cross-slip probability.