Kink Deformation Research Articles

Developing a novel phase balance of duplex stainless steel for exceptional mechanical properties and corrosion resistance

The classical ferrite-austenite balance of duplex stainless steel is still challenged by fulfilling an ultimate balance between mechanical property and corrosion resistance. In this work, a novel phase-balanced metastable structure is in-situ developed using additive manufacturing via para-equilibrium transformation controlled by interstitial nitrogen diffusion. The novel phase-balanced structure comprises a primary fine equiaxed intragranular austenite, an incomplete partitioning of alloying elements, a predominate Kurdjumov-Sachs orientation relationship of ferrite/austenite interface and a high-density dislocation. Synergistic breakthrough of both mechanical property and corrosion resistance is endowed, where excellent yield strength is attributed to the high-density dislocation and the fine austenite, high ductility is facilitated by triggering stacking fault and kinking deformation from the dramatic increase of stacking fault energy, and extraordinary corrosion resistance is credit to the incomplete partitioning of alloying elements. This work expands the microstructure design framework for high performance materials.

Multi-scale finite element analysis of laser-assisted forming of CF/PEEK composite corner structures

Laser-assisted forming can significantly increase the forming efficiency of thermoplastic composites. However, when forming CF/PEEK curved corner structures using laser-assisted forming, bending spring-back generated by the prepreg tape constrains the shape accuracy of the component. The bending deformation of unidirectional resin matrix composite materials is highly nonlinear. In this study, a multi-scale finite element method is used to obtain the bending properties of CF/PEEK composites for bending spring-back phenomenon of thermoplastic composite samples and predict the spring-back angle of CF/PEEK corner structures fabricated via laser-assisted forming. The average material properties were first calculated using RVE. Following this, a mesoscale model was developed to analyze kink deformation of the composite. Finally, the macroscopic prepreg bending spring-back was calculated. It was determined that the main mechanism of corner forming corresponds to the occurrence of a fiber kinking phenomenon on the interior of the corner. Furthermore, spring-back deformation is caused by residual stresses resulting from insufficient fiber kinking. The accuracy of the simulation results is verified via corner forming experiments. This study contributes to a deeper understanding of the spring-back mechanisms of laser-assisted forming of corner structures and provides a theoretical guidance for precision forming of multilayer thermoplastic composite bent structures.

Effect of heat treatment on microstructure evolution and strengthening-toughening behavior of high-strength Mg-Gd-Y-Zn-Zr alloy fabricated by wire-arc additive manufacturing

Mg-Gd-Y-Zn-Zr alloy is an important lightweight material in the aerospace field. Wire arc additive manufacturing (WAAM) provides a new route to fabricate large Mg alloy components. Here, a Mg-8Gd-4Y–1Zn-0.5Zr (wt.%) alloy was fabricated using WAAM based on the cold metal transfer (CMT) process. Subsequently, a short-time solid solution + aging treatment was designed to tailor the microstructure. In the as-fabricated condition, the microstructure mainly consisted of fine α-Mg, network (Mg,Zn)3(Gd,Y) eutectic phase, and lamellar γ′ basal precipitate. After 500 °C-1 h short-time solid solution, the eutectic phase rapidly dissolved, the long-period stacking ordered (LPSO) phase formed, and the fine grain was maintained. Due to the good deformation capacity of the fine grains and the kinking deformation capacity of the LPSO phase, the ductility was significantly improved from 5.2 ± 0.4% to 15.5 ± 1.1%. After further 200 °C-64 h artificial aging, dense β′ prismatic precipitates formed. Thanks to the synergistic strengthening of the fine grains and β′ prismatic precipitates, a yield strength of 242 ± 4 MPa was achieved. However, the kinking deformation of the LPSO phase was inhibited, resulting in a drastic decrease of ductility to 6.1 ± 0.5%. Overall, the combination of strength and ductility of the CMT-based WAAM-processed Mg-Gd-Y-Zn-Zr alloy under an optimized heat treatment regime can be superior to those of the cast Mg-Gd-Y-Zn-Zr alloys with similar contents of Gd and Y elements. This work can guide further performance optimization for WAAM-processed Mg-Gd-Y-Zn-Zr alloys.

Kinking induced plasticity in a novel refractory high-entropy alloy

A novel Ti41V27Hf13Nb13Zr6 refractory high-entropy alloy (RHEA) with an excellent fracture elongation of 30 % at a high strength level of 986 MPa was successfully fabricated. We discovered that kinking induced plasticity, involving successive stages of dislocation arrangement, pre-kinking, and the coalescence of multiple kink bands. The soft character of kinking originated from the degraded dislocation density within the kink bands. As such, the interplay between strain hardening caused by dislocation accumulation and the softening effect due to kink bands led to a plateau-type engineering stress-strain curve to large strains. These findings provide a novel design pathway to achieve ductile RHEAs via deformation kinking.

Scalable Microwires through Thermal Drawing of Co-Extruded Liquid Metal and Thermoplastic Elastomer.

This article demonstrates scalable production of liquid metal (LM)-based microwires through the thermal drawing of extrudates. These extrudates were first co-extruded using a eutectic alloy of gallium and indium (EGaIn) as a core element and a thermoplastic elastomer, styrene-ethylene/butylene-styrene (SEBS), as a shell material. By varying the feed speed of the co-extruded materials and the drawing speed of the extrudate, it was possible to control the dimensions of the microwires, such as core diameter and shell thickness. How the extrusion temperature affects the dimensions of the microwire was also analyzed. The smallest microwire (core diameter: 52 ± 14 μm and shell thickness: 46 ± 10 μm) was produced from a drawing speed of 300.1 mm s-1 (the maximum attainable speed of the apparatus used), SEBS extrusion speed of 1.50 mm3 s-1, and LM injection rate of 5 × 105 μL s-1 at 190 °C extrusion temperature. The same extrusion condition without thermal drawing generated significantly large extrudates with a core diameter of 278 ± 26 μm and shell thickness of 430 ± 51 μm. The electrical properties of the microwires were also characterized under different degrees of stretching and wire kinking deformation which proved that these LM-based microwires change electrical resistance as they are deformed and fully self-heal once the load is removed. Finally, the sewability of these microwires was qualitatively tested by using a manual sewing machine to pattern microwires on a traditional cotton fabric.

Making titanium alloys ultrahigh strength and toughness synergy through deformation kinks-mediated hierarchical α-precipitation

Titanium alloys engineered in structural applications achieve ultrahigh strength primarily through precipitation strengthening of secondary α-phase (αs) during aging, while they often experience compromised ductility and toughness due to traditional strength-toughness tradeoff. In this study, we propose a novel strategy to address this conflict by introducing deformation kinks prior to conventional cold rolling (CR) and aging processes. These kinks are produced by cold forging (CF) to create macroscopic lamellar structures in β-grains, which alter strain partitioning during subsequent CR and ultimately tailor αs-precipitation upon aging. As a result, an ultrafine duplex (αe + β)-structure is formed within kink interiors, while hierarchical αs-precipitates are generated in the external β-matrix. This unique microstructure effectively enhances dislocation activity, promotes uniform plastic strain distribution and impedes crack propagation. Consequently, a simple Ti-V binary titanium alloy exhibits exceptional properties with ultrahigh strength ∼1636 MPa, decent ductility ∼5.4 % and appreciable fracture toughness ∼ 36.1 MPa m½. The synergetic properties surpass those obtained through traditional CR and aging processes for the alloy and even outperform numerous multielement engineering titanium alloys reported in literature. Our findings open up a new avenue for overcoming the strength-toughness tradeoff of ultrahigh-strength titanium alloys, and also offer a facile production route towards structural materials for advanced performance.

Deformation mechanism and minimum energy path in Silicon–graphite composites with lattice defects

Edge-on atomic layers in layered solids undergo buckling, which creates a structure referred to as a “ripplocation.” A collective set of multiple ripplocations is referred to as a “ripplocation boundary.” In this study, in order to investigate the impact of lattice defects on ripplocation, we investigate the buckling deformation of graphene with lattice defects under confinement. To this end, we conducted confined uniaxial compression simulations by placing graphene sheets with various lattice defects between silicon atomic layers. Different types of lattice defects affect the mechanical properties of graphene, the results show that Young's modulus of graphene with the (1,0)_5 dislocation pair was the maximum at 494.6 GPa, whereas the Young's modulus of the (1,2)_10 dislocation pair was the minimum at 309.5 GPa. In addition, we employed a differential geometry method to study the out-of-plane deformation of a single-layer graphene system. Further, we used the nudged elastic band method for various types of lattice defects in graphene to uncover the minimum transition pathways, activation energy required to move from the (1, 0) dislocation pair to the (1, 1) pair is 44.916 eV. In particular, the results indicate that graphene with lattice defects exhibit kink deformation after buckling compared to that of perfect graphene. Our study not only explores the deformation of ripplocations and kink boundaries in layered solids but also provides a more comprehensive description influencing lattice defects on the nucleation mechanism and mechanical changes of ripplocations in graphene.

Kink-mediated high strength and large ductility via nanocrystallization in a tough titanium alloy

Titanium (Ti) alloys, which are highly promising as structural materials in critical industrial applications, generally require high strength and ductility, particularly high fracture toughness. However, the conventional approach of enhancing strength through mechanical processing to induce dislocations often leads to a compromised ductility known as the strength-ductility trade-off. Here, we develop a new strategy of the nanocrystallized kinks to overcome this issue in Ti-11V metastable β-Ti alloys via combining industrially used cold forging (CF) and cold rolling (CR) processes. Deformation kinks are firstly activated by CF, and subsequently they are fragmented into nanograins during CR, architecting nanocrystallized kinks in the coarse-grained matrix. This unique microstructure effectively balances the strength-ductility conflict, endowing this Ti-V binary alloy with high yield strength ∼1200 MPa, appreciable ductility ∼17 % and high fracture toughness ∼ 52.0 MPa·m½, which is superior to numerous multielement engineering Ti alloys. This design strategy of nanocrystallized kinks can be extended to other engineering materials, e.g., Mg and Zr alloys, for advanced performance at large industrial scales.

Microstructure, texture evolution and mechanical anisotropy of Mg-Gd-Y-Zn-Zr alloy sheets produced by unidirectional and cross rolling

The unidirectional rolling (UR) and cross rolling (CR) were used to process the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr (wt.%) alloy sheets. The effect of rolling routes on microstructure, texture evolution, and mechanical anisotropy was investigated. The deformed grains in UR alloy were gradually elongated along the RD, and the intragranular lamellar LPSO phase also transforms into a rod-shaped structure during rolling. For CR alloy, the occurrence of dynamic recovery results in the LPSO phase remaining lamellar shape during rolling, and the deformed grains are rounder than those in UR alloy. After rolling, UR alloy exhibits a texture with basal pole deviates from ND toward the location between TD and RD, which is caused by the synergistic effect of limited twinning, basal and prismatic slip. The CR alloy shows a texture with basal poles deviating from ND to RD 15.6°, which results from the activation of basal slip, pyramidal slip, and multiple twinning variants. The UR alloy exhibits approximately isotropic in yield strength and anisotropy in elongation, while the CR alloy presents a completely different result. The anisotropy in yield strength of CR alloys is related to their texture distribution and remarkably different basal slip Schmid factor in three tensile directions. The isotropic in elongation of CR alloys can be explained by the distribution frequency of tilt angles between basal poles and tensile directions, as well as the kink deformation of lamellar LPSO phase.

Evaluation of disclination Frank vector in ridge kink microstructure

ABSTRACT This study conducts dislocation-based modelling and numerical analysis to clarify the presence of disclinations within kinked deformation microstructures using the framework of differential geometry. Although the existence of disclinations has long been postulated, a mathematical foundation for this phenomenon still needs to be provided. In this study, we develop kink deformation models using planar arrays of edge dislocations. The dislocation density is represented using a level-set function, and the governing equations are solved numerically through the finite element method. We then introduce the holonomy method to demonstrate the presence of disclinations by quantitatively measuring the Frank vector. At first, we validate the accuracy of the method by comparing it with the theoretical predictions provided by the grain boundary theory. Subsequently, we performed qualitative validation of the model by comparing the macroscopic deformation observed in experiments. Finally, we evaluate the Frank vector within the ridge kink model, providing quantitative evidence for the presence of disclinations in the kinked deformation microstructure. We also illustrate the distribution of elastic stress fields generated by disclinations at the termination point of the kink interface.

Effects of Y substituting Gd on the microstructure evolution, mechanical properties and dissolution behaviors in the Mg-Gd-Ni alloys used as fracturing plugging tools

In this work, the effects of substituting 3 wt% Gd with 3 wt% Y on the microstructure, mechanical properties, and corrosion behaviors in the Mg-Gd-Ni alloys were investigated. By substituting Gd with Y, the area fraction of bulk-shaped long-period stacking ordered phases (LPSO) increases, while one of eutectic Mg2Ni phase decreases slightly. Moreover, it also promotes the precipitations of lamellar LPSO phase and nanoscale stacking faults (SFs). The tensile tests showed that the addition of Y increased the yield strength by about 40 MPa, mainly due to the strengthening of the kink deformation of the bulk shaped LPSO phase, the hindering effect of the lamellar LPSO and SF on dislocation movement, and the strengthening caused by grain refinement. As a result, the Mg-5Gd-3Y–5Ni (MGYN) alloy exhibits excellent mechanical properties with tensile yield strength (TYS) of 288 MPa, ultimate tensile strength (UTS) of 364 MPa, and elongation (EL) of 8.3 %. Moreover, although the fraction of Mg2Ni phase with high electrochemical potential is decreased, the reduction in dissolution rate is not significant because the discontinuous distribution of lamellar LPSO in the grains intensifies the galvanic corrosion by increasing the proportion of cathode phase. As a result, the coexistence of Mg2Ni and LPSO phases can observably improve the dissolution rate. Finally, the highest dissolution rate (234.56 mg cm−2 h−1 in 3 wt% KCl solution at 93 °C) reported so far for the dissoluble magnesium alloys can be attained for MGYN alloy in this study. This work provides an economical material selection with high dissolution rate and sufficient strength for the fabrication of the fracturing plugging tools.

Effect of Zn/Y atomic ratio on precipitation behavior and dynamic recrystallization behavior of Mg–Zn–Y alloy under different extrusion temperature

Precipitation behavior and dynamic recrystallization (DRX) behavior of Mg–Zn–Y alloys with different Zn/Y atomic ratios under different extrsuion temperatures were systematically investigated in this work. The results shows that the types of precipitated phases in the casted alloys are changed with the increase of Zn/Y atomic ratio. After extrsuion, the brittle W-phases in Mg98.7Zn1Y0.3 and Mg98Zn1Y1 alloys are broken into finer particles along the extrusion direction, but the resistance of W-phases to grain growth is weak at higher extrusion temperature. However, Mg97.5Zn1Y1.5 alloy exhibits relatively stable grain size at different extrusion temperatures, due to the significant inhibitory effect of LPSO phases on grain growth at high temperatures. The banded LPSO phases with wide phase spacing can promote DRX behavior via particle stimulated nucleation (PSN) resulting in highest DRX fraction. Nevertheless, the lamellar LPSO phases could effectively hinder the grain boundary migration and dislocation motion, which is against the nucleation and growth of DRX grains. It is precisely due to the influence of LSPO phases on the DRX behavior and its own kinking effect that Mg97.5Zn1Y1.5 alloy has better heat resistance. Mg97.5Zn1Y1.5 alloy exhibits excellent tensile strength and ductility, with ultimate tensile strength (UTS) of 413 MPa, yield strength (YS) of 330 MPa and elongation (EL) of 12.1% after extrusion at 573 K. The good ductility is mainly due to the coordinated deformation ability of the LPSO phase and the activated non-basal slip effect. The synergistic effect of lamellar LPSO phase and kinking deformation effectively refines the microstructure of the alloy and improves the strength.

Mechanics and Energetics of Kink Deformation Studied by Nonlinear Continuum Mechanics Based on Differential Geometry

This study conducts dislocation-based modeling and numerical analysis for kink deformation using the theory of nonlinear continuum mechanics based on differential geometry. The kinematics of the continuum is represented by the reference, intermediate, and current states, which are related to the multiplicative decomposition of the deformation gradient into plasticity and elasticity. The intermediate state is determined by the Cartan first structure equation, whereas the current state is obtained from the stress equilibrium equation. Kink deformation is modeled by a planar array of edge dislocations, and the governing equations are solved numerically using the finite element method. Quantitative verification of the model is conducted by comparing the bending angle at a kink interface and the theoretical prediction given for the tilt grain boundary. We construct two types of ortho-type kink models for several interface lengths to understand the energetics and mechanics of the kink growth process. The present numerical analysis demonstrates the significant stress concentration at the growth front due to the formation of wedge disclination. We also discuss the material strengthening mechanism from elastic strain energy, nonsingular stress fields, and nonlinear elastic interaction between the disclinations.

Microstructure and mechanical properties of the Mg98.5Zn0.5RE1 (RE=Gd and/or Y) alloys processed by equal channel angular pressing

In this work, Mg98.5Zn0.5RE1 (RE = Gd and/or Y) and Mg97Zn1Y2 (at%) alloys were subjected to homogenization and equal channel angular pressing (ECAP) to systematically compare the microstructure evolution and mechanical properties. The results indicate that, instead of the lamellar LPSO phases in the as-cast Mg-Zn-Y series alloys, the β-Mg5(Gd, Zn) phases appear in the as-cast Mg98.5Zn0.5Gd1 alloy which tend to be dissolved during homogenization. The furnace cooling after homogenization promotes the precipitation of numerous lamellar LPSO phases in all the studied alloys which inhibit the DRX behavior but facilitate the operation of kinking deformation during ECAP for the Mg98.5Zn0.5RE1 alloys, especially the Mg98.5Zn0.5Gd1 one. After the 5p-ECAP process at 350 °C, the larger density of kink bands, more LAGBs (low-angle grain boundaries) and lower SFB (Schmid factor for basal slip) combine to endow the Mg98.5Zn0.5Gd1 alloy with the higher strength-ductility synergy, exhibiting the tensile yield strength (TYS) of 214 MPa and elongation of 9.6%. The Mg97Zn1Y2 alloy with the larger volume fraction of interdendritic LPSO phases and dynamically recrystallized (DRXed) regions exhibits the superior ultimate tensile strength (UTS) of 277 MPa and moderate elongation of 7.2%.

Quasi in-situ investigation on kinking behavior of Fe-Cr-Al alloy during thermal compression

As a rare plastic deformation mechanism, kinking has attracted substantial attention because of its additional softening effect on the matrix and its heterogeneous refinement on the original grains. However, the details of kinking deformation and the influence of crystal orientation on itself have not been sufficiently elucidated yet, thereby resulting in inadequate microstructure optimization associated with kinking. In this work, the kinking formation process in Fe-Cr-Al alloy during thermal compression deformation has been investigated by using quasi in-situ electron backscatter diffraction (EBSD). By employing the average Schmid factor (Average-SF) model, the influence of crystal orientation on kinking behavior is predicted accurately. The results suggest that the softening effect of kinking on the matrix can be attributed to the fact that the nucleation of pre kink bands (pre-KBs, misorientation <15°) leads to a pronounced reduction in geometrically necessary dislocations (GNDs) density within them. Besides, the ripening behavior of pre-KBs is closely associated with the variation of GNDs density and the overall slip activation capability of the matrix, and is essentially dependent on crystal orientation. The harder the crystal orientation, the smaller the Average-SF, the higher the increment rate of GNDs density, the larger the ripening rate pre-KBs. Under equivalent strain, orientations close to 〈111〉// compression direction (CD) have the highest probability of forming mature KBs with high angle grain boundaries (HAGBs, >15°), whereas KBs in those close to 〈001〉//CD almost always remain as pre-KBs with low angle grain boundaries (LAGBs).

Compressive Deformation Characteristics of Nb2Co7 as Crystalline Mille-Feuille Structured Material

The uniaxial compressive deformation characteristics of single-phase Nb2Co7 were investigated by an electron backscatter diffraction analysis focused on microstructural evolution and kink formation in order to determine whether this monoclinic intermetallic phase is a novel crystalline “mille-feuille” structured (MFS) material. During uniaxial compressive deformation, Nb2Co7 does not behave brittle but shows high plasticity. In some microstructure regions, kink-like structures are observed, showing no delamination. In kink-free regions, the frequency of boundaries with rotation angles of 60°, 120°, and 180°, which correspond to changes in the monoclinic stacking vector of Nb2Co7 layers between adjacent close-packed (CP) layers, increases significantly after the compression test. The interfaces in the kink-like structures are low-angle boundaries with rotation axes within basal (001) planes. The rotation angles and axes of interfaces in the kink-like structures take various values, suggesting that the origin of the kink-like structures is not twinning, but in fact, these structures are a result of deformation kinking. Deformation of single-phase Nb2Co7 is considered to occur due to dislocation glide on basal (001) planes and kink formation, which is regarded as playing an indispensable role in the plasticity of Nb2Co7 during compression. It can therefore be concluded that Nb2Co7 is a novel crystalline MFS material.

Revealing the deformation behavior and microstructure evolution in Mg-12Y–1Al alloy during hot compression

In this study, the hot uniaxial compression of the heat-treated Mg-12Y–1Al alloy containing long-period stacking ordered (LPSO) phase was conducted by a Gleeble-3500 simulator. Compressive mechanical properties at elevated temperatures and the effects of deformation temperature (300–450 ℃) and strain rate (0.001–1 s−1) on the hot deformation behavior of the alloy were systematically investigated. Combining with an optical microscope (OM), electron backscatter diffraction (EBSD), and in-grain misorientation axes (IGMA) analysis, the microstructure and texture evolution, dislocation slip, and dynamic recrystallization (DRX) mechanism of the alloy was studied in detail. The results showed that the flow stress decreased with the increase in temperature and the decrease in strain rate. At a strain rate of 1 s−1, the compressive strength at 300 ℃ and 350 ℃ was basically the same. After deformation, the morphology of Al2Y had almost no change, while the LPSO underwent apparent kinking deformation. The increase in temperature was conducive to DRX. The DRX mechanism of the alloy mainly included discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), and DDRX was dominant. The dense lamellar LPSO at the grain boundary was detrimental to the occurrence of DDRX. In addition, the deformed microstructure presented a typical [0001]//CD (compression direction) texture. With the increase in temperature, the texture intensity decreased progressively due to the activation of multiple slip systems and the increased DRX fraction. At a strain rate of 0.01 s−1, when the temperature increased to 450 ℃, the number of deformed grains dominated by pyramidal Ⅱ<c+a> slip increased substantially.

STEM-EELS/EDS Chemical Analysis of Solute Clusters in a Dilute Mille-Feuille-Type Mg–Zn–Y Alloy

Dilute Mg-Zn-Y alloy with a mille-feuille structure (MFS) exhibits a mechanical strength comparable to Mg-Zn-Y alloy with long period stacking/ordered (LPSO) structure through kink deformation. In order to deepen understanding the thermal stability of the MFS-type Mg alloys, it is required to clarify the solute cluster structures composed of Zn and Y in solute enriched stacking faults (SESFs). In this study, electron energy-loss and energy dispersive X-ray spectroscopy based on scanning transmission electron microscopy (STEM-EELS/EDS) were conducted to investigate the electronic structure and composition of Zn and Y in the SESFs of the MFS-Mg alloy. Zn-L2,3 spectra indicated that the valence charges of Zn in the dilute Mg alloy were different from that of the LPSO-type Mg-Zn-Y alloy. In addition, the intensity ratio of L3/L2 in Y-L2,3 spectrum of the dilute MFS-Mg alloy was larger than that of the LPSO-Mg alloy, reflecting the electron occupancies of 4d3/2 and 4d5/2 orbitals of Y atoms were different from those of the LPSO-Mg alloys. STEM-EELS analysis of the SESF composition in the dilute MFS-Mg alloy indicated that the Zn/Y ratio should be lower than that of the LPSO-Mg alloy, which was confirmed also by STEM-EDS measurements. These results indicate that the cluster structure in the SESFs of the dilute MFS-Mg alloy should be different from the ideal Zn6Y8 cluster in the LPSO-type Mg-Zn-Y alloys.

Synergetic deformation mechanisms in an Mg-Zn-Y-Zr alloy with intragranular LPSO structures

Deformation kink is one of the important strengthening mechanisms of the long-period-stacking-ordered (LPSO) phase containing magnesium (Mg) alloys, while the deformation twin is generally suppressed. To optimize the mechanical properties of LPSO containing Mg alloy by simultaneously exciting kink and twin, we successfully prepared the Mg-Zn-Y-Zr alloy featuring intragranular LPSO phase and free grain boundary LPSO phase by homogenization. We unraveled the corresponding strengthening and toughening mechanisms through transmission electron microscopy characterization and theoretical analysis. The high strength and good plasticity of the homogenized alloy benefit from the synergistic deformation mechanism of multiple kinking and twining in the grains. And the activation of kinking and twinning depends on the thicknesses of LPSO lamellae and their relative spacing. These results may shed light on optimizing the design of Mg alloys regulating the microstructure of LPSO phases.

Two-Directional Micro-Laue Diffraction Mapping to Observe Kink Deformation in Long-Period Stacking-Ordered Mg–Zn–Y Alloys under Compression

We modified a previously developed compact compression-test stage for synchrotron radiation micro-Laue diffraction mapping to investigate the deformation of the long-period stacking-ordered phase of a magnesium polycrystal. This modification made it possible to obtain grain-boundary images from two orthogonal directions, realizing to obtain depth information about the position of kink formation. Also, to compare bulk and surface images, a long-focus optical microscope, which can take photographs of the surface morphology of the sample, was introduced into the apparatus.