Search

The article combines issues related to biaxial fatigue loading, corrections for equivalent stress calculations, and the practical application of new knowledge regarding biaxial fatigue in the aviation industry. It considers the possibility and expediency of taking into account the anisotropy of metals' mechanical characteristics in aircraft repair procedures, such as patching and replacing damaged skin panels. The biaxial loading of the skin is shown to be a significant factor that should be considered in the aircraft skin repair process. It is shown that while well-known Huber-Mises formula works well for isotropic materials, the fuselage skin made of anisotropic alloys requires corrections to the Huber-Mises method. For aircraft parts subjected to biaxial loading, the assessment of equivalent uniaxial stresses can be done by introducing the crystallographic factor into the Huber-Mises formula. This is achieved by transforming the biaxial stress components of fuselage loading due to pressurization and bending into the resolved stresses in the activated crystallographic slip systems of the dominant texture. [ABSTRACT FROM AUTHOR]

A novel nonlocal lattice particle method for modeling elastic deformation of cubic crystals was proposed and verified in this paper. Different from all other numerical models, the lattice particle method decomposes the grain domain into regularly packed discrete material particles according to the internal crystal lattice. Two most common Bravais cubic lattices, i.e., the body-centered cubic lattice and the face-center cubic lattice, were studied in this work. Model parameters were derived in terms of the three elastic material constants based on energy equivalency and theory of hyper-elasticity. Different from coordinates transformation used in the classical continuum mechanics theory, rotation of the discretization lattice is employed to equivalently represent the material anisotropy while capturing the underlying microstructure in the proposed model. The validity and prediction accuracy of the proposed model were established by comparing the predicted directional Young's modulus and the resolved shear stress of different slip systems against analytical solutions. [ABSTRACT FROM AUTHOR]

The elastic calculation needs five independent engineering constants for transversely isotropic material, such as HT ht . [Extracted from the article]

Abstract Fretting fatigue damage can significantly reduce the service life of Ni-based single crystal (NBSX) superalloys turbine blades. In this work, we proposed a fretting fatigue life prediction method by considering cracking, wear and their mutual interaction. Specifically, a parameter, denoted as RA , is developed with combination of R esolved shear stress based damage factor and A ccumulated dissipated energy based damage factor, by which the contribution from cracking and wear are described respectively. The proposed method is validated with experimental data in the literature. Finite element analyses are performed to study the distribution of stresses and strains. Results show that the predicted crack initiation site, failure plane and life cycles are consistent with the experimental results. Highlights • Considering the effects of crystal orientation on fretting fatigue behavior of Ni-based single crystal superalloy (NBSX). • Resolved shear stress and accumulated dissipated energy are used to describe the damage of cracking and wear, respectively. • The fretting fatigue damage of NBSX is quantified with comprehensive consideration of both cracking and wear. [ABSTRACT FROM AUTHOR]

Micromechanical deformation behaviors of E-form fine grain (EFG), E-form coarse grain (ECG), and AZ31 magnesium (Mg) alloys were investigated and compared using a mini-V-bending test. EFG and ECG Mg alloys with a weaker texture showed better bendability compared with AZ31 alloy that has a stronger texture. The evolution of the microstructure and microtexture during the mini-V-bending process was experimentally analyzed via an electron back-scattered diffraction (EBSD) technique. This study was focused on the effect that deformation twinning exerts on the strain localization and crack initiation. The twin bands (TBs) developed in the tension zone of bent specimens found to be closely related to the strain localization and crack initiation during the mini-V-bending process. A resolved shear stress (RSS) criterion and microstructure based crystal plasticity finite element method (CPFEM) were used to theoretically predict the activation of { 10 1 ¯ 2 } tension (TTW) and { 10 1 ¯ 1 } compression (CTW) twins in Mg alloys under a mini-V-bending process. RSS analysis indicated that EFG and ECG Mg alloys are more favorable for the activity of TTW and less favorable for the activity of CTW when compared with AZ31 Mg alloy during a mini-V-bending process. However, RSS analysis was not effective in quantitatively predicting twin development. The relative activities of six deformation modes, accumulated twin fractions, and accumulated plastic strains were simulated via microstructure-based CPFEM modeling. Compared with RSS analysis, CPFEM precisely explained the twin behavior that has been experimentally observed in ECG and AZ31 Mg alloys. • The effects of initial texture and grain size in Mg alloys under mini-V-bending tests were investigated. • The micromechanical deformation behavior was studied using EBSD analysis, RSS criterion, and mesoscale CPFEM modeling. • Deformation twinning was more prominent in ECG and EFG Mg alloys than in AZ31 Mg alloy during the mini-V-bending. • In contrast to the RSS criterion, CPFEM modeling more accurately described the twin behavior observed in the experiments. • The primary deformation mode in ECG and AZ31 Mg alloys was basal a and pyramidal c + a slip, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Elastic fields due to dislocation pile-ups are computed in heterogeneous media. • Grain boundaries with finite thickness and specific stiffness are considered. • The Peach–Koehler force can exhibit a change of sign with the dislocation position. • Grains misorientation has the predominant effect on dislocation pile-up length. • Rise of grain boundary stiffness push back dislocations and reduce caused stress. Abstract Elastic fields due to single dislocations and dislocation pile-ups are computed in heterogeneous media like bi-materials, half-spaces and tri-materials thanks to the Leknitskii–Eshelby–Stroh formalism for two-dimensional anisotropic elasticity. The tri-material configuration allows to consider grain boundary regions with finite thickness and specific stiffness. The effects of these parameters are first studied in the case of a single dislocation in a Ni bicrystal. Image forces may arise because of both dissimilar grain orientations and the presence of a finite grain boundary region. In particular, it is shown that the Peach–Koehler force projected along the dislocation glide direction can exhibit a change of sign with the dislocation position. Therefore, an equilibrium position in the absence of applied stress can be found by coupling an attractive compliant grain boundary region with a repulsive orientation of the adjacent crystal, or a repulsive stiff grain boundary region with an attractive orientation. Regarding dislocation pile-ups, it is shown that the resolved shear stress scales approximately with the inverse of the square root distance from the leading dislocation in the pile-up. This scaling law remains valid in anisotropic elasticity for the chosen heterogeneous media. Both the grain boundary stiffness and grains misorientation influence pile-up length and resolved shear stress, but the effect of misorientation is clearly seen to be predominant. In the case where the leading dislocation is unlocked, the resolved shear stress at a given position in the neighboring grain is reduced when the grain boundary stiffness is increased due to the pushing back of dislocations from the grain boundary. Graphical abstract Variation of the projected image force F im of a single edge dislocation with the distance from the grain boundary for different tri-material configurations (two infinite Ni grains + a grain boundary of finite thickness H = 5| b | and specific stiffness characterized by λ). Anisotropic vs. isotropic elasticity. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The effects of the secondary crystal orientations on the nickel-based single-crystal superalloy turbine blades were investigated. The stress concentration features were used for investigation of the optimal secondary crystal orientation leading to the higher strength of the single-crystal turbine blades. The crystal plastic finite element method coupled with micromechanics constitutive model is applied to study the effect of secondary crystal orientation on plastic deformation and mechanical behavior around the cooling holes and notches with the primary (load) orientation fixed at [001] direction. For nickel-based superalloy plates with holes or notches, the secondary crystal orientation effect on the strength needs to be clarified at various load levels. The maximum von Mises stress in the single-crystal alloy varies significantly with variation in the secondary crystal orientations. It was found that only two slip systems dominate the deformation process of the material owing to their favorable orientation with loading. The secondary orientation of 45° was identified with lowest resolved shear stress in the dominating slip systems and potential of producing higher strength for single-crystal turbine blades. [ABSTRACT FROM AUTHOR]

High resolution electron beam induced current (EBIC) imaging technique successfully visualized defect accumulation process in single crystal silicon under compression fatigue loading at 50 °C with the relative humidity of 75%. Dark line-like defect contrast emanating from deep-etched stress concentration notch appeared in EBIC images in a scanning electron microscope, after a certain number of fatigue cycles, but they were mostly invisible with secondary electron. This line-like defect contrast eventually extended along the direction which was expected in correspondence to one of the crystal slip systems of silicon with the largest resolved shear stress. Hence it is strongly suggested that crystal slips take place in bulk silicon under repeated loading, which presumably leads to local stress concentration and further to fatigue fracture especially in case tensile stress is applied in fatigue cycles. [ABSTRACT FROM AUTHOR]

The onset of frictional failure and potentially seismogenic deformation in carbonate rocks undergoing exhumation within fault zones depends on hardening processes that reduce the efficiency of aseismic dislocation-mediated deformation as temperature decreases. However, few techniques are available for quantitative analysis of dislocation slip system activity and hardening in natural tectonites. Electron backscatter diffraction maps of crystal orientations offer one such approach via determination of Schmid factors, if the palaeostress conditions can be inferred and the critical resolved shear stresses of slip systems are constrained. We analyse calcite marbles deformed in simple shear within the Karakoram Fault Zone, NW India, to quantify changes in slip system activity as the rocks cooled during exhumation. Microstructural evidence demonstrates that between ∼300 °C and 200–250 °C the dominant deformation mechanisms transitioned from dislocation-mediated flow to twinning and frictional failure. However, Schmid factor analysis, considering critical resolved shear stresses for yield of undeformed single crystals, indicates that the fraction of grains with sufficient resolved shear stress for glide apparently increased with decreasing temperature. Misorientation analysis and previous experimental data indicate that strain-dependent work hardening is responsible for this apparent inconsistency and promoted the transition from dislocation-mediated flow to frictional, and potentially seismogenic, deformation. [ABSTRACT FROM AUTHOR]

In this paper, the viewpoint that maximum resolved shear stress corresponding to the two slip systems in a nickel-based single crystal high-temperature fatigue experiment works together was put forward. A nickel-based single crystal fatigue life prediction model based on modified resolved shear stress amplitude was proposed. For the four groups of fatigue data, eight classical fatigue life prediction models were compared with the model proposed in this paper. Strain parameter is poor in fatigue life prediction as a damage parameter. The life prediction results of the fatigue life prediction model with stress amplitude as the damage parameter, the fatigue life prediction model with maximum resolved shear stress in 30 slip directions as the damage parameter, and the McDiarmid (McD) model, are better. The model proposed in this paper has higher life prediction accuracy.

Based on crystal plasticity theory, plate specimens with a cooling hole were adopted to investigate the stress distribution and crystallographic slip characteristics, the effects of crystallographic orientations taken into consideration. The slant angles are 0°, 15°, 30° and 45°. The results show that severe stress concentrations and high stress gradients present at the cooling holes. Stress distribution changes significantly with different slant angles and crystallographic orientations. Slip bands advancing to specific directions initiate around the holes and the characteristics of the slip band vary with slant angles. Four apparent maximum values occur along the hole in the three orientations and the locations of the maximum values are much dependent on the slant angles. The influences of slant angle on the activating law of the slip systems are remarkable. [ABSTRACT FROM AUTHOR]

Highlights: [•] The elasto-plastic features of 8YSZ were systematically studied by nanoindentation. [•] Hardness of 8YSZ exhibits interesting ISE at different scales. [•] Resolved shear stress distributions were estimated by Hertzian contact theory. [•] The results are useful for estimating potential erosion resistances of coating. [Copyright &y& Elsevier]

Abstract: The purpose of this study is to investigate the effects of a nano-scale stress-field on fatigue damage in a nano-copper component under fully-reversed and high-cycle loading. A resonant fatigue experiment is carried out for a cantilever micro-specimen that has a polycrystalline nano-Cu sandwiched by Si, Ti and SiN. Crystallographic slip bands associated with extrusion/intrusion of about 30nm width, which is much finer than that in the bulk copper (≈1μm), are formed on the Cu surface owing to the high-cycle fatigue loading. The new finding, the ultra-fine extrusion/intrusion, suggests the existence of different fatigue damage mechanisms in the nano-Cu from that in a bulk counterpart. The slip bands appear only in a particular grain though some others possess slip systems with higher Schmid factor. Detailed stress analysis, taking into account the Cu grains and surrounding dissimilar materials (Si, Ti, SiN), indicates that they are formed at a slip system with the highest resolved shear stress, which is in nano-scale. The formation stress is much higher than that in a bulk. [Copyright &y& Elsevier]

A form of plate specimen with a laser formed film cooling hole was designed to simulate Ni based single crystal cooling blade. The roundness error of the holes was obtained by image measuring instrument and low cycle fatigue (LCF) experiments were carried out at 900°C. The profile of real film cooling hole was assumed to be an ellipse and the roundness error was expressed as the difference of the major and minor radii of the ellipse. A group of elliptical holes with different roundness errors and a real hole were selected for finite element modelling. A crystallographic plastic finite element method (FEM) was used to analyse the resolved shear stress, damage distribution and LCF life of the models. Experimental and numerical results show that the fatigue crack growth path observed by optical microscopey is consistent with FEM analysis. A slip damage model based on crystallographic plastic theory is confirmed to have the ability to predict the LCF life of nickel based single crystal with consideration of roundness. Moreover, the roundness error can lead to a significant decreasing of the life of specimen with cooling hole and the larger the roundness error, the shorter the LCF life. An approximate quadratic curve is found to fit the relationship between the roundness error of hole and the logarithmic fatigue life. [ABSTRACT FROM AUTHOR]

Abstract: A resolved shear stress (RSS) criterion and the microstructure-based-crystal plasticity finite element method (MB-CPFEM) were used to analyze the activation of twin variants in extruded AZ31 Mg alloys during ex situ uniaxial compression. The RSS criterion, which is simply based on the Schmid factor, failed to predict the activation of twin variants consisting of the second-highest RSS and the third-highest RSS. In contrast to the RSS criterion, the MB-CPFEM based on a quasi-3D finite element mesh successfully predicted the activation of twin variants consisting of the highest RSS and the second-highest RSS. The MB-CPFEM demonstrated that local fluctuation of the stress field induces the activation of twin variants with the second-highest RSS during uniaxial compression. [Copyright &y& Elsevier]

Abstract: The effect of low-temperature on the active deformation mechanism is studied in pure copper. For this purpose, cryogenic wire drawing at liquid nitrogen temperature (77K) was performed using molybdenum disulfide lubrication. Microstructural investigation and texture analysis revealed severe twin formation in the cryogenically drawn copper, with a broad twin size distribution. The spacing of the observed deformation twins ranges from below 100nm, as reported in previous investigations, up to several micrometers. The extent of twin formation, which is significantly higher when compared to other cryo-deformation techniques, is discussed with respect to the state of stress and the texture evolution during wire drawing. [Copyright &y& Elsevier]

Abstract: In this research parallel molecular dynamics (MD) simulations have been performed to study the deformation behavior of nanocrystalline copper samples with embedded nanotwins under approximately uniaxial tensile load. Simulation results reveal that twin boundaries (TBs) act as obstacles to dislocation movements that lead to the strengthening of nanotwinned structures. However, easy glide of dislocations parallel to the TBs contribute primarily to the plastic strain or ductility of these materials. At higher deformation stages, the strengthening effects reach a maximum when abundant dislocations begin crossing the TBs. Due to this highly anisotropic plastic response of the grains, a random polycrystalline sample will show combined properties of ductility and strength. The strengths of the nanotwinned models are found to exhibit an inverse relationship with the twin width and temperature. We also investigate the relation between the deformation behavior in different grains, their orientation with respect to the loading direction, and ultimately the observed response of nanotwinned structures. [Copyright &y& Elsevier]

This paper describes fatigue damage evaluation for micro-nanoscale single-crystal silicon (SCS) structures toward the reliable design of microelectromechanical systems subjected to fluctuating stresses. The fatigue tests, by using atomic force microscope (AFM), nanoindentation tester, and specially developed uni-axial tensile tester, have been conducted under tensile and bending deformation modes for investigating the effects of specimen size, frequency, temperature, and deformation mode on the fatigue life of SCS specimens. Regardless of frequency and temperature, the fatigue life has correlated with specimen size. For example, nanoscale SCS specimens with 200 nm in width and 255 nm in thickness have showed a larger number of cycles to failure, by a factor of 105, at the same stress level, as compared to microscale specimens with 48 μm in width and 19 μm in thickness. Deformation mode has also affected the lifetime; however, no frequency and temperature dependences have been observed unambiguously in the S—N curves. The stress ratio parameter corresponding to the ratio of peak stress to average fracture strength has enabled us to estimate the lifetime for each deformation mode. To predict the fatigue life of SCS structures regardless of deformation mode and specimen size, we have proposed an empirical parameter that includes the resolved shear stress. The mechanism of fatigue failure of SCS structures is discussed from the viewpoint of dislocation slip, crack nucleation, growth, and failure through observations using AFM and scanning electron microscope. [ABSTRACT FROM AUTHOR]

Abstract: The growth characterization of an isolated spherical void in the grain boundary of anisotropic bicrystals was studied. The emphasis was placed on the role of the grain boundaries (perpendicular, tilt and parallel grain boundary) with respect to the external mechanical loading. The three-dimensional rate-dependent crystallographic model was applied in this paper. It is found that the resolved shear stress has a constant value in the mid-section of two grains. And there is high stress gradient and high stress concentration near the grain boundary, especially close to the void. The stress concentrations and growth of the void are greatly dependent on crystallographic orientations of grains and loading direction. The void grows more easily in the grain boundary perpendicular to the loading direction. In addition, the existence of void induces a complex activation of slip systems. [Copyright &y& Elsevier]

Abstract: Superficial Pleistocene karstic coatings found in the boundary region between the Iberian and Betic Chains (Spain) are often offset by normal faults. These travertines were sampled to investigate whether mechanical twins in calcite can develop at low paleodepths. Surprisingly, twinned grains are very abundant in sparry grains, which are found in the proximity of the fault planes (mean twin densities 28 twins/mm). Paleostress determinations based on the analysis of calcite e-twinning yielded the same principal stress orientations as the fault population analysis, i.e. a NW–SE extension tectonic regime. Therefore, calcite e-twin analysis is a useful method with which to establish the orientation of recent stress tensors. Calcite e-twins develop under conditions of minimum overburden (∼300m) during fault slip. The low differential stresses during the fault slip event suggest that the critical resolved shear stress on the twin plane must be lower than the expected mean value of 10MPa or that local stresses experienced by rock in and near the fault zone exceed ambient stress conditions during fault slip. [Copyright &y& Elsevier]

Abstract The Nojima Fault in Awaji, Hyogo prefecture, Japan, was ruptured during the 1995 Hyogo-ken Nanbu earthquake (MJMA = 7.2). Toshima is located close to the fault segment, in which a large dislocation has been observed on the Earth’s surface. Ikuha is near the southern end of the buried fault that extends from the surface rupture. Stresses are measured on core samples taken at depths of 310 m, 312 m and 415 m at Toshima and a depth of 351 m at Ikuha. The measured stresses show that both sites are in the field of a strike–slip regime, but compression dominates at Toshima. Defining the relative shear stress as the maximum shear stress divided by the normal stress on the maximum shear plane, the relative shear stress ranges from 0.42 to 0.54 at Toshima and is approximately 0.32 at Ikuha. While the value at Ikuha is moderate, those at Toshima are comparably large to those in areas close to the inferred fault of the 1984 Nagano-ken Seibu earthquake. Value amounts greater than 0.4 suggest that there are areas of large relative shear stress along faults, thus having the potential to generate earthquakes. Provided that the cores are correctly oriented, the largest horizontal stresses at shallow depths are in the direction from N113°E to N139°E at Toshima and N74°E at Ikuha, indicating that the fault does not orient optimally for the stress field at both sites. The slip is known to be predominant in the right-lateral strike–slip component. Although this slip may appear contradictory to the stress field at Toshima, the slip direction is found to be parallel to the measured stresses resolved on the fault plane for the first approximation. The ratio of shear stress to normal stress on the fault plane is roughly estimated to be greater than zero and smaller than 0.3 near Toshima. [ABSTRACT FROM AUTHOR]

Although the deformation behavior of high-entropy alloys (HEAs) has been extensively studied at the macroscale, many important properties have yet to be explored for these alloys at the microscale, thus hampering accurate prediction of damage and failure processes. Synchrotron high-energy diffraction microscopy (HEDM) and fast-Fourier transform-based crystal plasticity modeling was conducted to investigate the three-dimensional (3D) grain-resolved micromechanical response for approximately 1,900 constituent grains within a single-phase FCC HEA up to 1% applied strain. The evolution of grain-resolved elastic strains, lattice reorientations, and maximum resolved shear stresses (mRSS) were evaluated to quantify elastic, yield, and fully plastic behavior. Overall, the initial critical resolved shear stress (CRSS), determined via in situ HEDM and companion modeling, was found to be > 20% higher than estimated using the classical polycrystalline Taylor factor (M = 3.06). However, a descriptive parameter based on the average grain-resolved Taylor factor (M ¯) was found to show excellent agreement with plastic yielding behavior observed within HEDM datasets. Noticeable deviations in HEDM lattice reorientations compared to both EVP-FFT simulations and classical predictions for FCC polycrystals were discovered, highlighting the complexity in correlating local lattice reorientations, Taylor, and Schmid factors with plastic response for this material at the grain-scale. Therefore, it is anticipated that the overall trends and parameter identification of 3D grain-resolved properties in this study can serve as an important foundation for continued mesoscale investigation on both well-established and newly developed Cantor-like HEAs. [Display omitted] [ABSTRACT FROM AUTHOR]

We investigate deformation twinning in a highly textured magnesium alloy plate of Mg-3.1%Al-0.9%Zn-0.4%Mn under edge-on impact with in situ , synchrotron-based, ultrafast X-ray diffraction measurements, and corresponding stress states are simulated with the finite element method. Deformation twinning and its anisotropy under the triaxial stress condition are explained by a statistical analysis of resolved shear stress. The critical resolved shear stress criterion is applicable under complicated stress conditions induced by high strain rate impact loading. Three typical simple stress conditions are further explored as verification and application cases: uniaxial-stress, uniaxial-strain, and plane-stress. Extension twinning in the magnesium alloy is prone to occur for impact loading applied perpendicular to the crystallographic c -axis, regardless of the exact stress conditions. [ABSTRACT FROM AUTHOR]

The elastoplastic transition of a metastable β-Ti alloy, Timetal-18, is studied using in-situ high energy synchrotron X-ray diffraction microscopy (HEDM). The measured evolutions of the complete elastic strain (and stress) tensor(s), resolved shear stress, lattice rotation and rotation of the stress state of the grains are compared with the predictions of the elasto-viscoplastic Micromechanical Analysis of Stress-Strain Inhomogeneities with fast Fourier transform (MASSIF) code instantiated with an experimentally measured microstructure which matched that of the sample. The preferred glide plane of dislocations with ½<111> Burgers vectors of the BCC alloy was explored. It was found that the polycrystalline stress-strain response could be equally well described by any of the candidate glide planes or combinations thereof (i.e., pencil glide). However, simulations involving slip on {112} planes yielded a marginally better description of the individual grain-level responses, as compared to the simulation involving only the {110} planes. The small (typically <1°) crystallographic reorientations that the grains undergo during the elastoplastic transition, are insufficient to permit discrimination between candidate slip modes. The resolved shear stress (RSS) distributions showed a sharp increase in skewness around macroscopic yield and it was found that the hardening during the elastoplastic transition is primarily due to intergranular interactions. Analysis of "hard" and "soft" grains suggests non-Schmid effects may be present, even in these low strain rate, room temperature experiments. Finally, examination of the individual responses revealed "strain softening" in some of the grains. Intragranular heterogeneity in the orientation and stress state are highlighted as important areas for future investigations, which may reveal answers to unresolved questions in this research. • The complete stress/strain tensors in individual grains of Timetal-18 was tracked throughout the elastoplastic transition. • The distribution of the maximum resolved shear stresses within individual grains becomes positively skewed at yield. • Strain hardening in elastoplastic transition is mainly from intergranular interactions, not dislocation density evolution. • The Zener anisotropy ratio is found to have a strong impact on stress/strain partitioning even beyond yielding. • Some grains undergo strain-softening i.e. the stress component parallel to the loading direction decreases with straining. [ABSTRACT FROM AUTHOR]

In this paper, the viewpoint that maximum resolved shear stress corresponding to the two slip systems in a nickel-based single crystal high-temperature fatigue experiment works together was put forward. A nickel-based single crystal fatigue life prediction model based on modified resolved shear stress amplitude was proposed. For the four groups of fatigue data, eight classical fatigue life prediction models were compared with the model proposed in this paper. Strain parameter is poor in fatigue life prediction as a damage parameter. The life prediction results of the fatigue life prediction model with stress amplitude as the damage parameter, the fatigue life prediction model with maximum resolved shear stress in 30 slip directions as the damage parameter, and the McDiarmid (McD) model, are better. The model proposed in this paper has higher life prediction accuracy. [ABSTRACT FROM AUTHOR]

Experimental quantification of the critical resolved shear stress (CRSS) at the level of unit dislocation glide is still a challenge. By using in situ nanoindentation in a high-resolution transmission electron microscope and strain analysis of the acquired structural images, the CRSS for the motion of individual dislocations on {110}⟨011⟩ slip system and glide dislocation re-emission from a tilt grain boundary in TiN are quantified. This work offers an approach to measure the local stresses associated with dislocation motion in high-strength materials.