Twin Boundaries Research Articles

Characterization of a copper matrix composite reinforced with nano/submicron-sized boron fabricated via spark plasma sintering

The addition of various reinforcing phases can improve the mechanical properties of copper. This study investigates the enhancement of the mechanical properties of copper by adding boron, focusing on overcoming the challenges associated with the homogeneous distribution of submicron/nanoscale secondary phases in metal matrix composites. Employing a combination of mechanical alloying and spark plasma sintering, a copper-boron composite containing 3 wt% boron was prepared. Scanning electron microscopy equipped with an electron backscatter diffraction detector and energy-dispersive X-ray spectroscopy was utilized to characterize the structure of the sintered samples and mechanically alloyed powder. A two-phase structure containing nano/submicron-sized boron distributed uniformly in the copper matrix was formed in the sintered sample. Instrumented micro-indentation tests were performed to characterize the mechanical behavior of the samples. The sintered composite sample exhibits significantly higher hardness than the sintered copper. The enhanced mechanical performance of the composite is primarily attributed to grain boundary strengthening and microstructural refinement, where nano/submicron-sized boron particles prevent grain growth and refine the microstructure, enhancing hardness and strength. Additionally, dispersion strengthening from hard boron particles and the presence of a high density of twin boundaries within the copper matrix increase resistance to dislocation motion and deformation, and further improving the material's mechanical properties. On the other hand, the composite sample exhibits increased electrical resistivity due to the boron’s role as electron scattering centers. Overall, this study provides a valuable strategy for the design and optimization of advanced copper-based composites with tailored mechanical and electrical properties.

Determination of five-parameter grain boundary characteristics in nanocrystalline Ni-W by scanning precession electron diffraction tomography

Determining the full five-parameter grain boundary characteristics from experiments is essential for understanding grain boundaries impact on material properties, improving related models, and designing advanced alloys. However, achieving this is generally challenging, in particular at nanoscale, due to their 3D nature. In our study, we successfully determined the grain boundary characteristics of an annealed nickel-tungsten alloy (NiW) nanocrystalline needle-shaped specimen (tip) containing twins using Scanning Precession Electron Diffraction (SPED) Tomography. The presence of annealing twins in this face-centered cubic (fcc) material gives rise to common reflections in the SPED diffraction patterns, which challenges the reconstruction of orientation-specific virtual dark field (VDF) images required for tomographic reconstruction of the 3D grain shapes. To address this, an automated post-processing step identifies and deselects these shared reflections prior to the reconstruction of the VDF images. Combined with appropriate intensity normalization and projection alignment procedures, this approach enables high-fidelity 3D reconstruction of the individual grains contained in the needle-shaped sample volume. To probe the accuracy of the resulting boundary characteristics, the twin boundary surface normal directions were extracted from the 3D voxelated grain boundary map using a 3D Hough transform. For the sub-set of coherent Σ3 boundaries, the expected {111} grain boundary plane normals were obtained with an angular error of <3° for boundary sizes down to 400 nm². This work advances our ability to precisely characterize and understand the complex grain boundaries that govern material properties.

Effect of hot rolling and annealing on microstructure, crystallographic texture, and mechanical properties of Fe11.5 Co20.6 Ni40.7 Cr12.2 Al7.8 Ti7.2 high entropy alloy

The evolution of microstructure and texture during the thermomechanical processing of a Fe-Co-Ni-Cr-Al-Ti dual phase high entropy alloy consists of L12 (γ′) ordered precipitates in the disordered FCC (γ) matrix and its effect on the mechanical properties was investigated. The as-cast alloy was annealed at 1100 °C after 25 % and 50 % hot rolling reduction. The grain size becomes finer, and a considerable amount of annealing twin boundaries (Ʃ3 boundaries) developed in the hot rolling and annealed (HRA) samples. The α-fiber (ND||<110>) texture and twin-related texture components increase after HRA treatment. The mechanical response at room temperature is evaluated employing hardness and uniaxial tensile tests. A significant reduction in hardness, from 448 ± 6 HV to 381 ± 12 HV, is observed in the 50 % hot rolled annealed sample compared to the as-cast sample. Additionally, the yield strength reduced from 779 to 595 MPa with an increment in the ductility from 12.5 to 17.2 % in the as-cast and HR50A samples, respectively. Finally, it has been demonstrated that the increase in coherent twin boundaries and grain size excluding twin boundaries, led to the observed mechanical behavior.

Deformation and microstructure radial gradient evolution of AZ31 magnesium alloy bar during three-roll skew rolling

AZ31 magnesium alloy bar with radial gradient microstructure was prepared by three-roll skew rolling process (TRS), and achieving an excellent combination of ductility and strength. To elucidate the formation mechanism of this gradient microstructure, the deformation behavior during rolling was analyzed through experiments and simulations. The simulation results indicated that the metal flow of the bar in a spatial helical trajectory during rolling, with the trajectory inclination angle gradually decreasing from the center to the surface, promoting dynamic recrystallization in the surface and near-surface regions. The radial equivalent strain decreased from 1.5 at the surface to 0.01 at the center, and the shear strain decreased from 0.051 at the surface to 0.00012 at the center. Experimental results showed that the grain size of the bars decreased from 49.77 µm at the center to 19.72 µm at the surface, and the tensile twin volume fraction decreased from 34.1 % to 19.4 %. Dynamic recrystallization predominantly occurred in the outer ring region of the bars, while significant {10−12} tensile twin activation was observed in the central region, with twin-induced dynamic recrystallization observed at the twin boundaries. Mechanical property tests demonstrated that the gradient structure endowed the bars with a favorable combination of strength and elongation, with hardness significantly increasing from 50 HV at the center to 90 HV at the surface. This indicates that the three-roll skew rolling technology effectively promotes dynamic recrystallization at the surface, and the resulting gradient microstructure achieves an excellent combination of strength and plasticity in magnesium alloy bars.

Oxygen-close-packed (310)-plane substrates of β-Ga2O3 grown by the casting method

The highly anisotropic crystal structure of β-Ga2O3 gives rise to a variety of crystal planes, among which the (310) plane is a potentially stable close-packed plane for the O sublattice. In this paper, we report the β-Ga2O3 single crystal and substrates with a (310) major plane grown by the spontaneous nucleation technique in the casting method. High-quality crystal growth and substrate processing were confirmed by the 25.67 arc sec full width at half maximum and the 0.25 nm surface roughness. The nanoindentation experiments revealed the (310) substrate's better elastic recovery than that of (100) substrate. The Young's modulus and hardness of (310) substrates were 200 and 7.6 GPa, respectively. The surface barrier height and the Schottky barrier height were 1.25 and 0.92 eV, respectively. First principles calculations identified the (310)-Ga-I plane as the most stable surface configuration of the (310) plane under oxygen-poor condition, with a surface energy density of 1.48 J/m2. The (310) twin boundary formation around the O sublattice has a high energy density of 0.55 J/m2, suggesting its unlikelihood of spontaneous formation. These properties of (310) plane facilitate a high-quality crystal processing and epitaxial growth, thus endowing potential applications in high-quality power devices. Furthermore, the growth and fabrication of the (310) plane provide a route toward understanding the properties of β-Ga2O3 and advancing the growth techniques of oxide crystals.

Hole-Carrier-Dominant Transport in 2D Single-Crystal Copper.

In 2D noble metals like copper, the carrier scattering at grain boundaries has obscured the intrinsic nature of electronic transport. However, it is demonstrated that the intrinsic nature of transport by hole carriers in 2D copper can be revealed by growing thin films without grain boundaries. As even a slight deviation from the twin boundary is perceived as grain boundaries by electrons, it is only through the thorough elimination of grain boundaries that the hidden hole-like attribute of 2D single-crystal copper can be unmasked. Two types of Fermi surfaces, a large hexagonal Fermi surface centered at the zone center and the triangular Fermi surface around the zone corner, tightly matching to the calculated Fermi surface topology, confirmed by angle-resolved photoemission spectroscopy (ARPES) measurements and vivid nonlinear Hall effects of the 2D single-crystal copper account for the presence of hole carriers experimentally. This breakthrough suggests the potential to manipulate the majority carrier polarity in metals by means of grain boundary engineering in a 2D geometry.

Quantum confinement effect in nanotwinned diamond

The success in enhancing diamond by introducing nanotwins opens a new frontier in the development of superhard materials. However, the underlying hardening mechanism of nanotwinned diamond (nt-diamond) remains elusive and a persistent research focus. In this study, we employ first-principles calculations to unveil the performance enhancement in nt-diamond mediated by quantum confinement effect. This effect is characterized by the non-uniform valence charge density of C-C bonds near the twin boundary, leading to incomplete bond breakage at the onset of elastic instability and identified as the key factor in delaying cracking. These findings not only contribute to establishing the theory of hardness in superhard materials, but also suggest new avenues for enhancing their mechanical performance through the introduction of heterogeneous structures and dopant atoms aligned with the principle of quantum confinement effect.

Size-dependent mechanical responses of twinned Nanocrystalline HfNbZrTi refractory high-entropy alloy

Atomistic simulations are performed to study the size-dependent mechanical responses of HfNbZrTi refractory high-entropy alloy (RHEA) containing ultrafine grains and highly oriented twin boundaries (TBs). The strength and flow stress of nanocrystalline RHEA (NC-RHEA) under tensile loadings are explored versus decreasing grain size d. The transition from classical Hall-Petch (HP) strengthening to inverse HP softening at a critical grain size dc = 5.91 nm is attributed to the change of plastic deformation mechanisms from dislocation emission and phase transformation to grain boundary (GB) activities. Besides, the intragranular TBs considerably enhance the strength of nanotwinned RHEA (NT-RHEA); the enhancing effect reduces with decreasing twin thickness λ. As the volume fraction of GB increases with decreasing d, GB activities dominate the plasticity of NT-RHEA and cause comparable mechanical properties with NC-RHEA. Moreover, the influences of dislocation glide, phase transformation and twinning on the mechanical properties of RHEA are quantified and separately analyzed to further verify our simulation results. Findings of this study not only promote insights into the nanostructure-property relation of HfNbZrTi, but also shed the light on performance enhancement through nanostructural design.

Unraveling nano-scale effects of topotactic reduction in LaNiO2 crystals

Infinite-layer nickelates stand as a promising frontier in the exploration of unconventional superconductivity. Their synthesis through topotactic oxygen reduction from the parent perovskite phase remains a complex and elusive process. This study delves into the nano-scale effects of the topotactic lattice transformation within LaNiO2 crystals. Leveraging high-resolution scanning transmission electron microscopy and spectroscopy, our investigations uncover a panorama of structural alterations, including grain boundaries and coherent twin boundaries, triggered by reduction-induced transformations. In addition, our analyses unveil the formation of an oxygen-rich disordered transition phase encircling impurities and pervading crystalline domains and the internal strain is accommodated by grain boundary formation. By unraveling these nano-scale effects, our findings provide insights into the microscopic intricacies of the topotactic reduction process elucidating the transition from the perovskite to the infinite-layer phase within nickelate bulk crystals.

The Impact of Perceived Community Services for the Elderly on Self-Rated Health: An Analysis Utilizing a Mediated Latent Growth Model.

This study aims to investigate the relationship between older adults' perceived community services for the elderly (PCSE), life satisfaction (LS), and self-rated health (SRH). Data from four rounds of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 2008 to 2018 were used. A total of 2454 older adults were obtained. Unconditional Least Squares (ULS) was used to measure PCSE, LS, and SRH growth trajectories without covariates. Finally, a mediating latent growth model was constructed using Mplus 8.3 to examine the mediating role of LS in the relationship between PCSE and SRH after adjusting for some demographic characteristics. The results from the ULS method indicate that the intercepts and slopes for PCSE and LS are significantly negatively correlated (β 1 = -0.629, β 2 = -0.579, p < 0.001). Additionally, there is a significant positive correlation between the intercept and slope of health levels (β = 0.774, p < 0.001). Using a parallel growth model, significant regression coefficients were found between the intercept of PCSE and the intercepts of SRH and LS (β 1 = -0.335, β 2 = 0.378, p < 0.01). Similarly, the regression coefficients between the slope of PCSE and the slopes of SRH and LS were also significant (β 1 = -0.532, β 2 = 0.344, p < 0.01). Furthermore, the regression coefficient between the intercept of LS and the intercept of SRH was significant (β = 0.415, p < 0.001). The regression coefficient between the slope of LS and the slope of SRH was also found to be significant (β = 0.729, p < 0.001). It is essential to ensure adequate supply and accessibility of community services for older adults. LS especially is, and should be a promising target for assessing the quality of life and utilization of PCSE supply.

Colloidal synthetic environmental design towards high-density twin boundaries and boosted thermoelectric performance in Cu5FeS4 icosahedrons

High-density twin boundaries can significantly influence materials’ functional and mechanical properties. In thermoelectrics, twin engineering is able to manipulate the carrier and phonon transport in semiconductors, leading to improved dimensionless figure of merit (zT). However, obtaining twin boundaries with tunable density and uniform distribution in thermoelectric semiconductors is rather challenging. Here, by precisely controlling the temperature of sulfur precursor, the particle size of synthesized Cu5FeS4 icosahedrons can be decreased to produce higher-density twin boundaries. Accordingly, the optimized average distance between two adjacent twin boundaries matches the mean free path of phonons but is much larger than that of carriers, thereby efficiently lowering the lattice thermal conductivity without affecting the carrier mobility significantly. In combination with the enhanced power factor caused by increased carrier concentration, a maximal zT of 0.95 is achieved at 773 K in a p-type Cu5FeS4 derivative material, which is one of the highest values among those in Earth-abundant, environmentally-friendly thermoelectric sulfides. This work uncovers the crucial role of high-density twin boundaries in decoupling the carrier and phonon transport for improved thermoelectric performance in Cu5FeS4-based materials.

Slip to twinning to slip transition in polycrystalline BCC-Fe: Effect of grain size

A slip-to-twinning-to-slip transition concerning grain size has not been reported in the literature on BCC-Fe so far. In the present investigation, we report slip-to-twinning and twinning-to-slip transitions at 8 nm and 20 nm grain sizes, respectively. For this purpose, we used molecular dynamics simulations to study ⟨110⟩ quasi-3D polycrystals of BCC-Fe with grain sizes ranging from 3 nm to 102 nm at 10 K. Hall-Petch and inverse Hall-Petch relations were obtained depending on the grain size. Grain boundaries (GBs) were converted to lower energy boundaries through twin-GB interactions. Nucleation of twin boundary through GB decomposition was observed even under the constraints of triple junctions. Various dislocation mechanisms were observed, like delayed slip transfer, slip absorption, dislocations from a twin boundary, and formation of debris/point defects/tubular-type cylindrical rods from the gliding dislocations. Dislocation activity was observed to increase with increasing grain size. Luster and Morris parameter was used to understand dislocation-GB interactions. Intergranular fracture was observed.

Atomic-resolution investigations on dislocation-assisted evolution of {10[formula omitted]3} twin boundaries in a magnesium alloy

{101¯3}〈303‾2‾〉 twinning is usually activated at the later stage of plastic deformation of Mg alloys, which is closely relevant to their fracture behavior. Reactions between slip dislocations and twin boundaries (TBs) are suggested to facilitate TB migration, retarding the premature TB cracking. Here, dislocation-assisted evolution of {101¯3} TBs in a Mg alloy subjected to cyclic deformation were studied and modeled, according to transmission electron microscopy observations, theoretical analyses of interfacial defects, and molecular dynamics simulations. Atomic-resolution experimental observations showed that symmetric tilt grain boundaries (STGBs) near the {101¯3} twin orientation with steps were generated in the deformed Mg alloy. Theoretical analyses and atomistic simulations indicated that transformation of {101¯3} TBs into the STGBs could occur by reactions with incident basal 〈a60〉 dislocations in pairs from the twin and matrix respectively under the normal stress. STGB steps would be produced by reactions of individual basal 〈a60〉 dislocations with GB dislocations at the STGB. Importantly, resultant steps could further emit {101¯3} twinning dislocations to facilitate the STGB migration. Moreover, STGBs near the {101¯3} twin orientation could evolve back into {101¯3} TBs either by reactions with an array of basal 〈a60〉 dislocations, or by a GB sliding of b = 〈303‾2‾〉 theoretically. Our results may provide insights into the mechanisms of {101¯3} TB evolution in Mg alloys, which plays important roles in their plastic deformation and plasticity.

Effects of Intrarenal Reflux on Renal Growth in Children With Grades III-V Primary Vesicoureteral Reflux.

The phenomenon of intrarenal reflux (IRR) has been considered a crucial link between vesicoureteral reflux (VUR) and segmental scarring. We conducted a study on renal length in 104 children diagnosed with Grades III-V VUR, with or without IRR, using contrast-enhanced voiding urosonography (ceVUS). The patients were divided into two treatment groups: the conservative antibiotic prophylaxis (CAP) group and the operation group, which were further categorized into two subgroups: the IRR group and the non-IRR group. Our findings revealed an incidence rate of 35.96% (41/114) for IRR occurrence, with 43.42% (33/76) occurring in upper renal segments, 32.89% (25/76) in lower segments, and 23.68% (18/76) in middle segments. In the CAP group where the effects of IRR persisted, the renal growth observed was as follows: IRR group-0.19 ± 0.13 cm; non-IRR group-0.39 ± 0.23 cm; contralateral negative group-0.66 ± 0.35 cm; control group-0.46 ± 0 .25 cm respectively (P < .05). In the operation group, where the effects of IRR were eliminated, the renal growth for the IRR group, non-IRR group, contralateral negative group, and control group was 0.46 ± 0.22 cm, 0.54 ± 0.31 cm, 0.67 ± 0 .42 cm, and 0.36 ± 0.17 cm respectively (P < .005). In conclusion, the presence of IRR can impact renal growth in children diagnosed with Grades III-V primary VUR. Following surgical intervention, the IRR kidney does not exhibit catch-up growth; however, it demonstrates parallel growth alongside the unaffected kidney. Conversely, the non-IRR kidney experiences catch-up growth. Therefore, for children presenting with Grades III-V primary VUR combined with IRR, a more aggressive treatment approach such as surgery is recommended.

New insights into selective leaching and ferritization in 15-15Ti austenitic steel in lead-bismuth eutectic through parent phase reconstruction

Selective leaching accompanied by ferritization is widely observed in the dissolution corrosion of austenitic steels exposed to lead-bismuth eutectic. This study proposes a refined mechanism for selective leaching involving solid-state diffusion followed by dissolution-reprecipitation processes. Pole figure analysis reveals that ferritization follows the Nishiyama-Wassermann orientation relationship, independent of corrosion environment or corrosion behavior. Moreover, austenite reconstruction analysis shows that the growth of ferrite is hindered by the misfits at random high-angle grain boundaries. Hence the above results suggest that ferritization is initially driven by solid-state diffusion. As LBE channels open within the grains, further growth of ferrite is assisted by the dissolution-reprecipitation mechanism. Additionally, the formation of dual-oriented ferrite grains at Σ3 twin boundary is observed, and the selectivity of this formation with respect to grain boundary and ferrite orientation is discussed.

Disconnection units of twinning in body-centered-cubic metals

Twin boundary (TB) migration, facilitated by the motion of disconnections, plays a pivotal role in the deformation of body-centered cubic (BCC) crystals. Comprehending the migration rules of twinning disconnections (TDs) under shear stress is significant in elucidating the role of twin migration in BCC plasticity. Nevertheless, our understanding of the atomic structure and migration mechanics of TDs remains incomplete. In this study, we employ the theory of interfacial defects and molecular dynamics (MD) simulations to thoroughly investigate potential {112}[111] TDs in BCC tantalum (Ta). These TDs are characterized by their Burgers vectors, which were predicted through related dichromatic pattern analysis. We reveal that single-layer and double-layer TDs represent the fundamental building blocks (units) of multi-layer TDs. Their migration directions are entirely opposite under the same shear loading, and they cannot annihilate each other when they migrate “face to face”. Furthermore, these migration rules governing single-layer and double-layer TDs offer a comprehensive explanation for the complex composition and decomposition patterns observed among various multi-layer TDs. What's more, we demonstrated that TDs with zero Burgers vector can only be driven as a whole under coupled loading conditions. These findings significantly enhance our understanding of TB migrations in BCC metals.

Unconventional hcp/fcc Nickel Heteronanocrystal with Asymmetric Convex Sites Boosts Hydrogen Oxidation.

Developing non-platinum group metal catalysts for the sluggish hydrogen oxidation reaction (HOR) is critical for alkaline fuel cells. To date, Ni-based materials are the most promising candidates but still suffer from insufficient performance. Herein, we report an unconventional hcp/fcc Ni (u-hcp/fcc Ni) heteronanocrystal with multiple epitaxial hcp/fcc heterointerfaces and coherent twin boundaries, generating rugged surfaces with plenty of asymmetric convex sites. Systematic analyses discover that such convex sites enable the adsorption of *H in unusual bridge positions with weakened binding energy, circumventing the over-strong *H adsorption on traditional hollow positions, and simultaneously stabilizing interfacial *H2O. It thus synergistically optimizes the HOR thermodynamic process as well as reduces the kinetic barrier of the rate-determining Volmer step. Consequently, the developed u-hcp/fcc Ni exhibits the top-rank alkaline HOR activity with a mass activity of 40.6 mA mgNi -1 (6.3 times higher than fcc Ni control) together with superior stability and high CO-tolerance. These results provide a paradigm for designing high-performance catalysts by shifting the adsorption state of intermediates through configuring surface sites.

The study of ([formula omitted]01) plane in β-Ga2O3 crystal

This study confirms that the symmetric plane of (001) with respect to the twin boundary in β-Ga2O3 is the (1¯01), and it has been systematically characterized. X-ray diffraction has determined that diffraction peaks appear only at positions where the l component of the miller indices hkl is even, and these positions coincide with the diffraction peak positions of the (001) plane. The termination atomic arrangement of the (1¯01) plane is not exclusively composed of gallium or oxygen atoms, it exists in two forms with hanging bond densities of 1.614 × 1015/cm2 and 2.421 × 1015/cm2, respectively. Wet etching experiments on the (1¯01) plane reveal distinct defect morphologies compared to the (001) plane, indicating its suitability for distinguishing between these two planes. The Raman modes of (1¯01) plane coincide with other crystal planes. Through optical transmission spectra, X-ray photoelectron spectra, and Ultraviolet photoelectron spectra, its bandgap width Eg of 4.76 eV, the valence band maximum EVBM of 3.64 eV and the Schottky barrier height Φsurf of 1.12 eV were determined. Compared to studies of other crystal planes, it is believed that the (1¯01) plane also possesses similar application potential.

Examining Self-Regulation and Problematic Smartphone Use in Canadian Adolescents: A Parallel Latent Growth Modeling Approach.

Despite extensive research on the prevalence and mental health implications of problematic smartphone use in adolescents, the cognitive mechanisms underpinning its development, such as self-regulation, remain underexplored. This study aims to fill this research gap by investigating the developmental trajectories of self-regulation and problematic smartphone use among Canadian adolescents. Participants (N = 1303; 614 girls; Mage = 14.60 years, SD = 1.16 years) attended one of five public high schools in Southern British Columbia. Adolescents self-reported their self-regulation skills, as well as problematic smartphone use annually for three years. In line with developmental expectations, results indicated that both self-regulation and problematic smartphone use increased across the three years. Parallel latent growth models revealed significant intercept and positive slope differences for self-regulation and problematic smartphone use, showing that higher initial self-regulation predicted lower initial problematic smartphone use, and vice versa. Girls exhibited higher initial levels of problematic smartphone use, but gender differences in developmental trajectories were not observed. These findings emphasize the importance of early self-regulation skills in preventing the escalation of problematic smartphone use in adolescents, providing evidence-based insights for developing targeted interventions.

Interactions between basal dislocation and [formula omitted] twin boundary in HCP metal: A molecular dynamics study

For hexagonal close-packed (HCP) metals having a c/a<3, basal <a> slip is the most common slip system, and {112̅2} twinning is one of the primary plastic deformation modes when compressive stress is applied along the c-axis. In this work, molecular dynamics simulations have been applied to reveal the interaction mechanism between different basal <a> dislocations and {112̅2} twin boundaries (TBs) in Mg, Zr and α-Ti. When the 000113[112̅0] dislocation interacts with the {112̅2} TB, it is transmuted into a 112̅2-{112̅1} double twin (DT). With increasing shear stress, the growth of the 112̅2-{112̅1} DT is impeded by the other side of the {112̅2} TB, it transmutes into (0001)13<101̅0> dislocations and twin dislocations (TDs). Furthermore, the {112̅1} TB is capable of transforming into a {112̅2} TB and a new co-zone {112̅1} TB, which then forms a twin-twin junction (TTJ) to release stress concentration. When the 000113[21̅1̅0] dislocation interacts with {112̅2} TBs, it transmuted into a I2 SFs in the twin and a TD with one-layer height on the {112̅2} TB. But the 000113[1̅21̅0] dislocation would be impeded by the {112̅2} TB and couldn’t be transmuted further.