Solid Microstructure Research Articles

Quasi-2D Model to Predict Solid Microstructure in Drying Thin Films.

The microstructure of solid coatings produced by solution processing is highly dependent on the coupling between growth, solute diffusion, and solvent evaporation. Here, a quasi-2D numerical model coupling drying and solidification is used to predict the transient lateral growth of two adjacent nuclei growing toward each other. Lateral gradients of the solute and solvent influence the evolution of film thickness and solid growth rate. The important process parameters and solvent properties are captured by the dimensionless Peclet number (Pe) and the Biot number (Bi), modified by an aspect ratio defined by the film thickness and distance between nuclei. By variation of Pe and Bi, the evaporation dynamics and aspect ratio are shown to largely determine the coating quality. These findings are applied to drying thin films of crystallizing halide perovskites, demonstrating a convenient process map for capturing the relationship between the modified Bi and well-defined coating regimes, which may be generalized for any solution-processed thin film coating systems.

Effect of annealing time on solid solution microstructure and memory properties of additive Fe-Mn-Si-Cr-Ni alloy

Annealing plays a pivotal role in optimizing the morphology and quantity of cooling martensite within the solid solution matrix of additively manufactured Fe-based memory alloys. In this study, we utilized laser filament deposition to create Fe-17Mn-6Si-9Cr-5Ni alloy, and subsequently compared the microstructure and memory properties of the alloy following two treatments: a 900[Formula: see text]C× 60 min solution treatment and a solid solution + annealing treatment at various durations at 600[Formula: see text]C. Our aim was to investigate how annealing time impacts the memory properties of additively manufactured Fe-Mn-Si-Cr-Ni alloys in their solid solution state, focusing on microstructural changes during the metamorphic and revertive states. The findings reveal that after the solution treatment, the alloy contains a higher number of cooling martensite units, but their arrangement is disordered, indicating a lower degree of order. However, after a 10 min annealing treatment, the quantity of cooling martensite slightly diminishes, while their arrangement becomes more orderly. With prolonged annealing, both the quantity of cooling martensite and the grain size of the alloy decrease significantly. Consequently, after a 10-min annealing treatment, the alloy exhibits a 31% increase in shape recovery rate under a 6% pre-deformation compared to the alloy subjected solely to the solution treatment, and the recoverable strain reaches 4.59%. This demonstrates that an appropriately timed annealing process can transform the disordered cooling martensite within the solid solution structure of additive manufacturing Fe-based memory alloys into a more regular arrangement, thereby enhancing their memory performance.

Effects of some polymeric additives on the cocrystallization of naproxen and nicotinamide via freeze drying

Crystallization of active pharmaceutical ingredients (APIs) has important implications for their bioavailability. Their dissolution behavior is affected by the phase, size, and dispersion of the crystal particles. Polymeric additives have served as effective modifiers of the API crystallization, and we tested their effects during the crystallization via freeze drying. Poly(vinylpyrrolidone), poly(vinylpyrrolidone-co-vinyl acetate), and poly(acrylic acid) were investigated for their effects on the cocrystallization of naproxen (API) and nicotinamide (coformer). We aimed to establish the types and concentrations of the polymers that modulated the size and dispersion of the particles without affecting the cocrystal phase. Poly(vinylpyrrolidone) (Mw 40000) and poly(vinylpyrrolidone-co-vinyl acetate) (Mw 45000–70000) at the concentration level of 3–5% were effective in this regard in increasing the initial and overall API dissolution, which was correlated with the microstructure of the freeze-dried solids. This study is intended to contribute to foundations for further research to apply crystal-modulating additives to the process of freeze drying.

Melt Network Reorientation and Crystallographic Preferred Orientation Development in Sheared Partially Molten Rocks

AbstractWe investigated the co‐evolution of melt, shape, and crystallographic preferred orientations (MPOs, SPOs, and CPOs) in experimentally deformed partially molten rocks, from which we calculated the influence of MPO and CPO on seismic anisotropy. Olivine‐basalt aggregates containing 2 to 4 wt% melt were deformed in general shear at a temperature of 1,250°C under a confining pressure of 300 MPa at shear stresses of τ ≤ 175 MPa to shear strains of γ ≤ 2.3. Grain‐scale melt pockets developed a MPO parallel to the loading direction by γ < 0.4. At higher strains, the grain‐scale MPO remained parallel to the loading direction, while incipient sample‐scale melt bands formed at ∼20° to the grain‐scale MPO. An initial SPO and CPO were induced during sample preparation, with [100] and [001] axes girdled perpendicular to the long axis of the starting material. At the highest explored strain, a strong SPO was established subperpendicular to the loading direction, and the [100] axes of the CPO clustered nearly parallel to the shear plane. Our results demonstrate that grain‐scale and sample‐scale alignments of melt pockets are distinct. Furthermore, the melt and the solid microstructures evolve on different timescales: in planetary bodies, changes in the stress field will drive a relatively fast reorientation of the melt network and a relatively slow realignment of the crystallographic axes. Rapid changes to seismic anisotropy in a deforming partially molten aggregate are thus caused by MPO rather than CPO.

Petrogenesis and possible fingerprints of the Najd shear system on the evolution of deformed granitic rocks in the west Wadi Nugrus area, Egypt

In this paper, we present petrological constraints on the geodynamic evolution of deformed granitic rocks in the west Wadi Nugrus area, south Eastern Desert of Egypt. The deformation belt trends NW-SE forming the so-called “Nugrus Shear Zone (NSZ)” a major tectonic feature in the Arabian-Nubian Shield (ANS) at the junction between Wadi El Gemal and Wadi Hafafit areas, namely “Site I″ and “Site II”. The deformed granitic rocks comprise highly sheared arc granitoids and post-collisional to within-plate younger granites. Although the investigated granitic rocks are highly deformed, they show no signs of metamorphism and retain their primary igneous minerals. The melts from which the investigated granitic types originated experienced considerable degrees of partial melting in the transitional lower crust/upper lithospheric mantle as indicated by the contents of incompatible and rare-earth elements (REEs). Typical A-type granites developed before deformation and during emplacement in a continental environment. Zircon has ThO2/UO2 > 0.1, which is typical of igneous zircon, which sometimes experiences little recrystallization during the late magmatic deuteric stage, either pre-or syn-deformational due to circulation of fluids along the shear zone. It is believed that the deformation of all granitic rocks in the west Wadi Nugrus area is possibly synchronous and related to the Najd Fault System (NFS). The (NFS) extends from the western Arabian Peninsula to develop the NW-trending Nugrus Shear Zone (NSZ) in the south Eastern Desert. Sub-magmatic, solid-state, and sub-solidus deformational microstructures are evidence for the deformation related to the (NFS). Chessboard patterns in quartz and sub-magmatic fractures in plagioclase indicate deformation at high temperatures (T > 650 °C) in the presence of melt, which demonstrate the shearing during granitic cooling. On the other hand, quartz grain boundary migration and sub-grain recrystallization are two examples of solid state-related high-temperature deformation-related microstructures (T > 450 °C). Mica kinks along feldspar twinning and bending planes refer to low-temperature sub-solidus microstructures (T < 450 °C).

Advanced Manufacturing of Unique Solid Oxide Fuel Cell Electrode and Electrolyte Microstructures through Aerosol Deposition

Development of various additive manufacturing technologies over the years has given an opportunity for highly customizable and unique structures to be fabricated with applications towards several different industries. For ceramic manufacturing, techniques such as direct ink writing (DIW), stereolithography (SLA), and fused deposition modeling (FDM) have been utilized to construct very complex structures. These technologies have also been developed for use towards solid oxide fuel cells (SOFCs) where they have been utilized to manufacture components greater than 200 µm in thickness. Some components of the SOFC such as the electrodes, electrolyte, and barrier layer are much smaller and consist of thicknesses from 1 µm to 50 µm. Along with the reduced thickness, the electrodes of a SOFC are often comprised of a composite material where the previously mentioned technologies struggle with achieving both the required high resolution and compositional change needed to manufacture these specific components. This project’s goal is to develop an additive manufacturing technique that suits both requirements for manufacturing the electrodes, electrolyte, and barrier layer of a SOFC.The technology that has been developed to complete the manufacturing of highly customizable electrodes along with the electrolyte and barrier layer is Aerosol Deposition. The Aerosol Deposition system contains several different elements that lead to consistently tailored microstructures for the various 3-D printed parts including the use of syringe pumps, an ultrasonic atomizing nozzle from Sonaer Ultrasonics, an infrared heater, and a flexible automation system. The ultrasonic atomizing nozzle is used to convert a stream of liquid into a fine mist via mechanical vibrations. The liquid that is supplied to our ultrasonic atomizing nozzle is low solids loading solvent-based suspension containing approximately 1 - 5 vol% of solids and polymer pore formers. Suspensions are supplied to the nozzle by mechanical pressure provided from a programmable syringe pump. This technology accompanied with a flexible automation system gives the potential for highly customizable and repeatable microstructures that can aid in evaluating variables associated with the different components of the SOFC.Development of the additive manufacturing system to fabricate the anode functional layer, electrolyte, barrier layer, and cathode active and current collector layers through an automated process have been studied. For the electrodes, a microstructure that contains approximately 30% - 40% porosity is suitable to enhance the electrochemical performance of the electrode. Sintering temperatures for the electrodes typically range from 1000 °C to 1300 °C which can typically densify the microstructure and restrict the amount of porosity present. To implement porosity within the microstructure poly(methyl methacrylate) was incorporated into electrode suspensions due to their ability to diffuse out of the electrode microstructure at temperatures of ~450 °C. The electrical and mechanical properties of the separate components have been characterized accordingly utilizing electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Acknowledgements: This work was performed in support of the US Department of Energy’s Solid Oxide Fuel Cell Program. The authors would like to acknowledge the WVU Shared Research Facilities (SRF) and thank Dr. Thomas Kalapos from Leidos Research Support Team for his assistance.

Thermal stability of laser track microstructures in an Al-Cr-Co-Mn-Zr I-phase alloy

Laser glazing of solid metal surfaces is an efficient and cost-effective way to evaluate the potential of an alloy system for use in metal additive manufacturing (MAM), but there are concerns about the stability of the resulting microstructures. Here it is shown that in situ transmission electron microscopy heating experiments on specimens cut from laser glazing tracks using focused ion beam methods can provide a useful insight into the transformation phenomena that occur upon reheating. Examples of such experiments are presented for laser tracks in a powder-processed Al-Cr-Mn-Co-Zr alloy, which contains a complex distribution of icosahedral quasicrystal (I-phase) dispersoids in a polycrystalline FCC Al matrix. Initial ramped heating experiments were performed to identify suitable conditions for isothermal studies of transformation pathways. Tracks with the lowest laser energy input exhibited supersaturated solid solution microstructures. These were stable during ramped heating to around 375 °C. For isothermal exposures at 400 °C there was precipitation of Al4(Cr,Mn) both at grain boundaries and within the FCC Al matrix phase. In tracks with higher laser energy input, equiaxed I-phase dispersoids were formed in the matrix. These microstructures were stable during ramped heating to around 400 °C. In isothermal experiments at 425 °C, there was precipitation of Al4(Cr,Mn), followed by the onset of I-phase decomposition. The partially decomposed dispersoids exhibited an I-phase core surrounded by a shell of Al45(Cr,Mn)7. In isothermal experiments at 450 °C, the dispersoids decomposed completely to form Al4(Cr,Mn), indicating that Al45(Cr,Mn)7 is a metastable intermediate transformation product. These observations provide a useful guide to the transformations that might occur during MAM processing of this alloy system.

The three-dimensional coarse-graining formulation of interacting elastohydrodynamic filaments and multi-body microhydrodynamics.

Elastic filaments are vital to biological, physical and engineering systems, from cilia driving fluid in the lungs to artificial swimmers and micro-robotics. Simulating slender structures requires intricate balance of elastic, body, active and hydrodynamic moments, all in three dimensions. Here, we present a generalized three-dimensional (3D) coarse-graining formulation that is efficient, simple-to-implement, readily extendable and usable for a wide array of applications. Our method allows for simulation of collections of 3D elastic filaments, capable of full flexural and torsional deformations, coupled non-locally via hydrodynamic interactions, and including multi-body microhydrodynamics of structures with arbitrary geometry. The method exploits the exponential mapping of quaternions for tracking 3D rotations of each interacting element in the system, allowing for computation times up to 150 times faster than a direct quaternion implementation. Spheres are used as a 'building block' of both filaments and solid microstructures for straightforward and intuitive construction of arbitrary three-dimensional geometries present in the environment. We highlight the strengths of the method in a series of non-trivial applications including bi-flagellated swimming, sperm-egg scattering and particle transport by cilia arrays. Applications to lab-on-a-chip devices, multi-filaments, mono-to-multi flagellated microorganisms, Brownian polymers, and micro-robotics are straightforward. A Matlab code is provided for further customization and generalizations.

Phase field model of microstructure formation during cooling slope slurry generation of novel Al-15Mg2Si-4.5Si composite

The present study discusses the development of a two-dimensional phase field model of semi solid microstructure evolution of the novel Al-15Mg2Si-4.5Si composite during cooling slope rheoprocessing. The superheated melt of the said composite undergoes partial solidification during its shear flow over the slope free surface, prior to get collected within the isothermal slurry holding furnace. Seed undercooling based nucleation model is adopted in the present PF model to simulate slurry microstructure of the composite. Experimentally determined cooling rate values are considered to simulate slurry microstructure for different process conditions. Micrographs of melt samples collected during experimentation establishes the developed PF model as an accurate microstructure prediction tool for the composite slurry. Apart from morphological features such as size and degree of sphericity values of the evolving primary Mg2Si and α-Al grains, the model predictions includes melt temperature as well as solid content at any given instant of slurry processing.

Metal Matrix Composite Developed with Marine Grades: A Review

Metal matrix composites (MMCs) are now one of the most significant groups of modern engineering materials as a result of the increased attention they have received in recent years. MMCs have recently been manufactured using a variety of technical specifications and techniques, with properties such as the ability to withstand thermal stability at the lowest possible cost, reduced weight and density, increased strength and toughness, and improved wear resistance. It is crucial to homogenize the distribution of the reinforcing phase during composite processing in order to generate particulate or fibrous solid microstructures, depending on the form of the reinforcing phase of the composite. This implies that new procedures must be employed to enhance the mechanical and microstructural properties of metal products. One of the answers to the above challenges is friction stir processing (FSP). FSP improves the surface quality, ductility, formability, strength, hardness, and fatigue life of metal alloys without altering the properties of metals in bulk. This study aims to review MMCs suitable for FSP-designed marine structures and identify knowledge gaps. According to the literature, MMCs are advanced materials capable of exhibiting microstructure, increased hardness, strength, excellent damping, wear, and reduced thermal expansion, making them suitable for a wide range of applications. Although FSP is recognized as a new secondary processing approach to enhance the microstructure and properties of MMCs, few studies have reported the production of MMCs suitable for marine applications. Therefore, this opens a large gap that needs to be filled and requires further investigation of MMCs development.

Grain Boundary Characterization and Potential Percolation of the Solid Electrolyte LLZO

The influence of different processing routes and grain size distributions on the character of the grain boundaries in Li7La3Zr2O12 (LLZO) and the potential influence on failure through formation of percolating lithium metal networks in the solid electrolyte are investigated. Therefore, high quality hot-pressed Li7La3Zr2O12 pellets are synthesised with two different grain size distributions. Based on the electron backscatter diffraction measurements, the grain boundary network including the grain boundary distribution and its connectivity via triple junctions are analysed concerning potential Li plating along certain susceptible grain boundary clusters in the hot-pressed LLZO pellets. Additionally, the study investigates the possibility to interpret short-circuiting caused by Li metal plating or penetration in all-solid-state batteries through percolation mechanisms in the solid electrolyte microstructure, in analogy to grain boundary failure processes in metallic systems.

A study on the application and accuracy of macro-scale topology optimization for flow devices containing solid microstructures

A study on the application and accuracy of macro-scale topology optimization for flow devices containing solid microstructures

High entropy nanomaterials for energy storage and catalysis applications

In the past decade, high entropy alloys have been a research field of interest largely attributed to the enormous possibilities in alloy compositions, solid solution microstructures, and enhanced properties. The progress accomplished so far in the innovative growth and development of the mechanical, nanomechanical, chemical, electrochemical properties for energy storage systems using high entropy alloys on the nanoscale has limited reports in the literature. Mastering the synthesis of high entropy alloys is the deciding factor, if not the holy grail, when interested in a new material. For nanoparticles, in particular, this is true. Hence, the study on the production of high entropy alloy nanoparticles (HE-NPs) and the impact of synthesis on the structure of the resulting nanomaterial is valid for newly emerging components like HEA-NPs and the linkages between synthesis, structure, and property are essential for creating HEA-NP-based applications for energy storage applications, requiring the creation of a fundamental protocol to enable their mass manufacture and efficiency in service. In this study, we have presented a straightforward review of high entropy alloys, recent advances in high entropy nanoparticles and their various syntheses for energy and catalysis applications.

A Method for Time-Resolved Characterization of Polarization-Induced Solid Oxide Cell Microstructure Evolution

Solid oxide cell long-term durability experiments are resource-intensive and have limited ability to capture the interdependence of microstructural evolution and electrochemical performance. Studies of microstructural degradation mechanisms are usually limited to before and after life-test images. Here we describe a life testing method that simultaneously operates multiple symmetric cells under different conditions, simultaneously providing information on electrolysis and fuel cell operation, while sampling the microstructure during operation. The method utilizes laser-cutting to exactly define different cell areas, allowing testing under different current densities with a single current source, and facilitating removal of segments of the cells during life tests, allowing for microstructural evaluation at intermediate times. The method is demonstrated in Ni-YSZ / YSZ / Ni-YSZ fuel-electrode-supported cells at low H2O/H2 ratios. Characterization using SEM-based imaging techniques shows pronounced microstructural damage that increases rapidly with increasing current density and time, mirroring observed electrochemical degradation. The present results agree with prior reports for SOC operation under such conditions but reveal new features of the degradation process via the unique capability of time-resolved imaging.

Characterization, fractionation, and compatibility properties of Litsea cubeba kernel oil with potential value for industrial application as a lauric acid-based oil source

Litsea cubeba kernels, produced as a by-product of L. cubeba essential oil, are rich in oils, particularly lauric acid. However, they are not adequately utilized. In this paper, L. cubeba kernel oil (LKO) was compared to traditional lauric acid-based oils (coconut oil [CNO] and palm kernel oil [PKO]) and a palmitic acid-based oil (palm olein, POL) to assess their compatibility and physicochemical differences. LKO fractions with various melting points were obtained. The fractions were analyzed for their acylglycerol composition, solid fat content, crystallization characteristics, polymorphism, and microstructure. LKO exhibited a complex fatty acid composition, including trace amounts of stearic acid (0.51%) and myristoleic acid (1.3%); small amounts of lauroleic acid (7.70%), capric acid (9.11%), and caprylic acid (10.89%); and a high amount of lauric acid (54.13%). The lauric acid content of the solid phase (LKST5) could be increased to 67.04 ± 0.96% after fractionation. In contrast to conventional lauric acid-based oils, LKO and its fractions are dominated by the β-form. In addition, the binary systems LKO/CNO and LKO/PKO displayed eutectic phenomena at XLKO= 0.9 and XLKO= 0.8, respectively. LKO/POL compatibility changed with increasing LKO ratio, gradually shifting from monotectic to eutectic to solid solutions. By analyzing the compatibilities and fractionation properties of LKO, potential industrial applications such as biodiesel and biolubricants can be explored. These uses would help promote the comprehensive use of oil by-products derived from oilseeds.

Structured lipids produced from palm-olein oil by interesterification: A controllable lipase-catalyzed approach in a solvent-free system

Palm olein (POL) was modified by enzymatic interesterification with different degrees of acyl migration in a solvent-free packed bed reactor. The fatty acid and acylglycerol composition, isomer content, thermodynamic behavior, and relationship between crystal polymorphism, solid fat content (SFC), crystal microstructure, and texture before and after modification were studied. We found that the increase in sn-2 saturation interesterification was not only due to the generated tripalmitin (PPP) but also caused by acyl migration, and the SFC profiles were changed accordingly. The emergence of high melting point acylglycerols was an important factor accelerating the crystallization rate, further shortening the crystallization induction time, leading to the formation of large crystal spherulites, thereby reducing the hardness. The transformation from the β' to the β form occurred during post-hardening during storage. The isomer content also affected the physicochemical properties of the modified POL.

Engineering linker defects in functionalized UiO-66 MOF nanoparticles for oil-in-water Pickering emulsion stabilization.

Designing metal-organic framework (MOF)-based solid nanoparticles to stabilize Pickering emulsions by fine-tuning their hydrophobicity and lipophobicity is vital for essential applications and fundamental understanding. We demonstrate in situ grafting of palmitic acid in UiO-66 MOF through its linker defects. Our designed and activated nanoparticles (denoted as UP') stabilized the Pickering emulsions of n-heptane-in-water. Furthermore, we showed how UP' stabilized emulsion droplets disperse in media by covering each tiny droplet with a nanoscale layer made of UP'. To support our claim, we carried out the freeze-drying process to remove the liquid part from the emulsion, leaving behind the solid shell-like microstructures that we further characterized through several microscopic techniques. The stable n-heptane-in-water emulsion was confirmed by dilution (drop test), conductivity, zeta potential, and theoretical surface electrostatic potential measurements. Rheological studies indicate that the Pickering emulsions of n-heptane-in-water stabilized by UP' are much more resistant to deformation and flow imparting higher (mechanical) stability and shelf-life. Pickering emulsions stabilized by UP' emerged as a versatile way to design smart functional materials of UiO-66 through engineering linker defects that may have potential applications in interfacial catalysis, dye or contaminant separation, etc.

Moldable Carbon Dot-Linked Elastomers for Three-Dimensional Arbitrary Fluorescent Structures

The integration of photoluminescent nanomaterials with a polymer matrix provides profitable chemical functionalities for the modern three-dimensional (3D) structure creation. Aiming at homogeneous nanomaterial generations inside moldable polymers, we report a direct carbon dot (CD) synthesis in a polydimethylsiloxane elastomer base. This approach is solvent-free without the need of dehydrating and condensation processes, enabling delicate solid 3D microstructure construction with minimal CD photoluminescence influence. The solubility of precursor species in an elastomer gel base plays the key role in generating photoluminescent nanomaterials inside a polymer matrix. This CD-linked elastomer prepared from (3-aminopropyl)trimethoxysilane (APTMS), therefore, exhibits higher fluorescence emission than that generated from the aminopropane precursor. Compared to propyltrimethoxysilane, the amino group-containing APTMS precursor provides nitrogen doping in produced CDs, accompanying an enhanced photoluminescence property. These moldable CD-linked elastomers entail a quantum yield of 7.2% and can be applied to create various structures and patterns on diverse substrates. Taking the anti-counterfeiting application as an example, the material offers the hybrid encoded information of chemical photoluminescence and physical structures to enhance the encryption level. This in situ CD generation in the polymer base approach enables arbitrary 3D structure creation with minimized fluorescence self-quenching effects.

A Modified Quantum-Inspired Genetic Algorithm for Continuum Structural Topology Optimization

Topology optimization and quantum computing have evolved rapidly over the past three decades. Previous topological optimum design methods suffered from financial burden and mathematical complexity. To overcome these shortcomings, a modified quantum-inspired evolutionary algorithm-based topology optimization method is proposed. This nested approach combines the classic solid isotropic microstructure with the penalization method and the double chains quantum genetic algorithm to establish an integral topology optimization framework. The former is utilized to determine the search direction of design variable updating. Meanwhile, the latter ensures abundant search diversity. The validity and feasibility of the developed methodology are eventually demonstrated by several application examples. The results indicate that the proposed optimization framework is independent of initial values and can lead to optimized structures. In addition, it will be more appropriate and effective if this strategy is deployed on a quantum computer in the future.

Composition design to tune the mechanical behavior of a TRIP-TWIP (CrMnFeCoNi)50 Fe50-xCrx multi-principal element alloys

The utilization of the laser melting deposition (LMD) method to synthesize the (CrMnFeCoNi)50Fe50-xCrx (x = 5, 10, and 15 at.%) multi-principal elements alloys (MPEAs) are successfully demonstrated. It discovers that all (CrMnFeCoNi)50Fe45Cr5, (CrMnFeCoNi)50Fe40Cr10, and (CrMnFeCoNi)50Fe35Cr15 MPEAs retain a single-phase solid solution microstructure, and the in-situ structure transformation found in the matrix is ascribed to the reduction of the stability of FCC structure via appropriately tailoring constituent elements. (CrMnFeCoNi)50Fe45Cr5 MPEA exhibits the simultaneous enhancement in the plasticity (almost 100%) and the tensile strength (from 415 MPa to 470 MPa) resulting from the co-contribution of deformation-induced twining and tiny amounts of precipitation for M23C6 carbide at ambient temperature. Inversely, (CrMnFeCoNi)50Fe35Cr15 displays remarkable improvement in the tensile strength (∼ 600 MPa) at the sacrificing of the plasticity elongation (from 50% to 32%) originating from the contribution of strain-induced structure transformation. Here, the transformation-induced twinning and transformation-induced ductility are successfully achieved by tuning the stability of the constituent phases in the (CrMnFeCoNi)50Fe50-xCrx MPEAs. These discoveries not only distinctly distinguish the tensile strength and plasticity of the (CrMnFeCoNi)50Fe50-xCrx MPEAs from the corresponding CoCrFeMnNi MPEA, but also pave the way for designing and enhancing the comprehensive properties of MPEAs and other structural materials for engineering applications.