Eutectic high entropy alloys (EHEAs) based on the AlTiVCr system offer a promising combination of high strength and ductility, making them attractive for advanced structural applications. In the present work, a simple and effective strategy of varying two constituent elements Al and Ti was proposed to design EHEA. AlxTi80-xV15Cr5 (x = 35, 40, 45 at.%) alloy compositions were prepared by arc suction casting. The Al35Ti45V15Cr5 alloy exhibited a single B2 phase structure. With increasing Al content, the microstructure of Al40Ti40V15Cr5 evolved to a dual-phase structure composed of a high amount of B2 matrix with locally distributed HCP phase, and the Al45Ti35V15Cr5 alloy formed as a eutectic structure consisting of B2 and HCP phases. The Al45Ti35V15Cr5 EHEA composition demonstrates a high yield strength of 1864 MPa and excellent compressive ductility of 14.3 %, attributed to the suppression of shear band propagation at the phase boundaries, and it exhibited a low density of 3.97 g/cm3, leading to a superior specific strength of 469.22 MPa cm3/g. The stable intermetallic-based eutectic microstructures were achieved by tuning the composition in accordance with the strong negative mixing enthalpy between Al and Ti. The formation of a eutectic dual-phase microstructure consisting of B2 and HCP phases significantly enhances the mechanical performance. These findings give a new pathway for designing lightweight, high-performance eutectic high entropy alloys.

With the increasing use of electronics and wireless communication, the implications of electromagnetic radiation have garnered significant attention. Recent advancements in the use of crystalline and amorphous fillers in polymer matrices for electromagnetic interference (EMI) shielding represent a noteworthy development. Tunable screen-printed polymer composite films, utilizing these fillers, enable the customization of magnetic and electrical properties essential for effective EMI shielding. The study indicates that polymer composites based on crystalline fillers (PCNF) possess a dielectric constant (e ') of 8.36 and dielectric loss (e '') of 6.51, alongside a magnetic permeability (mu ') of 8.24 and magnetic loss (mu '') of 6.59. In comparison, amorphous filler composites (PAM) show superior values: e ' = 10.94, e '' = 8.32, mu ' = 10.55, and mu '' = 8.94. The research emphasizes the critical role of structural design in enhancing the shielding performance of these fillers. The preparation of EMI shields through a detailed screen-printing technique is discussed, complemented by simulations conducted with CST Studio Suite Software to analyze electric and magnetic field dynamics. Experimental evaluations reveal that the crystalline composite PCNF achieves an EMI shielding efficiency (EMI SE) of 53.66 dB, while the amorphous composite PAM surpasses this with an EMI SE of 78.8 dB. Reflection-loss assessments further validate these results, with PCNF exhibiting a reflection loss (RL) of -52.9 dB and PAM showing RL of -50.68 dB, indicating predominant absorption in the EMI shields. Overall, the study highlights that the amorphous PAM composites deliver superior EMI shielding efficiency and absorption, making them promising candidates for future lightweight EMI shielding technologies.

Balancing strength, ductility and multifunctionality in aluminum matrix composites (AMCs) represents a long-standing challenge because of the inherent trade-offs between mechanical performance and functional properties. Conventional reinforcement approaches using carbon nanotubes (CNTs) and graphene-based materials often suffer from agglomeration, weak interfacial bonding and insufficient load transfer, limiting their strengthening potential. To overcome these drawbacks, this study presents a gradient-laminated (GL) CNT + RGO hybrid/Al composite incorporating a 3D-interconnected hybrid network of CNTs and reduced graphene oxide (RGO) within a four-layer hierarchical design. This bio-inspired gradient architecture, fabricated by a dry-wet smart coating process followed by annealing, ensures uniform dispersion of the nanocarbon reinforcements and formation of robust interfacial bonds. The hybrid 3D CNT-RGO network not only strengthens the composite through improved load transfer, crack bridging and dislocation prevention, but also maintains high electrical and thermal conductivity by mitigating excessive electron and phonon scattering. As a result, the GL CNT + RGO hybrid/Al composite proposed in this study achieves a remarkable yield strength of similar to 388 MPa, a tensile strength of similar to 503 MPa and a uniform elongation of similar to 22 %, significantly outperforming conventional AMCs. At room temperature, the composite exhibits a thermal conductivity of similar to 280 W/mK and an electrical conductivity of similar to 88 % International Annealed Copper Standard (IACS), which decrease slightly to similar to 260 W/mK and 82 % IACS at 200 degrees C, demonstrating excellent multifunctional performance. The exceptional mechanical properties result from the synergistic strengthening mechanisms of grain boundary stabilization, high dislocation storage and optimized strengthening by nanocarbon networks. This study presents a scalable design strategy also integrating finite element simulations and experimental testing for next-generation high-performance AMCs, and provides a transformative route for applications requiring high strength, superior thermal management and excellent electrical conductivity, particularly in the aerospace, automotive and electronics industries.

The synergistic enhancement of strength and ductility remains an urgently demanded challenge for refractory high entropy alloys (RHEAs). Here, we propose a novel preexisting twinning strategy to achieve excellent strength-ductility synergy. Advanced crystallographic analysis and molecular dynamics simulations reveal that the mechanism of preexisting {112}<111> twinning enhances the ductility via inducing rotational twinning. The rotational twins serve as an effective slip transfer interface and dislocation reaction node, which facilitates the local strain coordination. More crucially, the following rotational twin modes have been identified: {1 (1) over bar4}<2<(21)over bar>>>, {1<(1)over bar >5}<5<(52)over bar>>, {1 (1) over bar7}<7<(72)over bar>>, {1 (1) over bar9}<9<(92)over bar>> (rotation around the common <110> pole), and a special {(21) over bar1}<111> mode, in stark contrast to the classical twinning shear mechanism. At 723-823 K, preexisting twins trigger early dynamic recrystallization, refine grain structures, and serve as nucleation sites for deformation twins, while atomic kinks along the rotational twin boundaries dynamically drive twin rotation and suppress crack propagation. Consequently, the non-equiatomic TiNbZrHfTa alloy reaches a remarkable yield strength of similar to 660 +/- 11 MPa with 20.74 +/- 1.26% elongation at 723 K, and elongations exceeding 17% at 823 K and 50% at 923 K, respectively, which successfully overcomes the intermediate-to-high-temperature embrittlement problem of RHEAs. Altogether, this work offers a transformative pathway for designing high-performance RHEAs for extreme environments.

Abstract The distinctly different mechanical behavior of nanocrystalline materials compared to their coarse-grained counterparts has been extensively studied using atomistic simulations and experimental works. In-situ TEM deformation has revealed multiple mechanisms, including grain rotation and deformation twinning. Yet the effect of elastic strain concentrations from mechanical anisotropy or dislocation pile-ups remains less understood, as precise measurements were previously limited to specifically oriented grains. Here, we show that combining precession nanobeam electron diffraction with advanced orientation and strain-mapping algorithms allows measurement of transient elastic strain fields across all grains in a sputter-deposited nanocrystalline Au thin film. During nominally elastic loading, we observe an increase in tensile elastic strain and substantial grain rotations exceeding 6°, with pronounced heterogeneity among individual grains. Analysis reveals that these rotations arise from a combination of grain size, initial strain state, and dislocation density. The importance of the initial microstructural state is further highlighted in annealed samples: reducing defect density delays yielding and triggers deformation twinning at similar length scales. These results demonstrate the feasibility of mapping elastic strains with high accuracy and nanometer resolution across arbitrary grain boundaries, and reveal the critical role of local strain heterogeneities in determining the deformation behavior of nanocrystalline materials.

Metal hydrides remain an intriguing alternative to conventional gaseous and liquid hydrogen storage methods, offering high volumetric storage density and enhanced hydrogen storage safety at ambient conditions. In this regard, the intermetallic compound FeTi is one of the most promising storage materials. However, its widespread industrial application remains challenging due to the need for activation, slow initial kinetics, large hysteresis, and high material costs. In this study, we aim to overcome these limitations by devising an alternative synthesis pathway to prepare nanoporous and ultra-fine porous FeTi with controlled grain and ligament sizes, allowing us to study the obtained well-defined microstructures in detail. In particular, we observe the confinement of the FeTi phase by surface oxides, which can be correlated with the hydrogen sorption properties of the respective material. These experimental results are further supported by an analytical model allowing the calculation of the absorption pressure as a function of microstructure-dependent elastic stresses. Additionally, we show that such stresses also influence the absorption-desorption hysteresis. This study lays the groundwork for the controlled and systematic study of the processing-structure-properties relations in metal hydrides and FeTi in particular, thereby paving the way to cost-effective and efficient hydrogen storage solutions based on metal hydrides.

Mg alloys have garnered significant attention in advanced engineering applications due to their exceptional combination of specific strength and lightweight properties. The α-Mg solid solution, which constitutes the core component of Mg alloys, directly governs the alloy’s thermodynamic behavior, kinetic response, and overall performance. This paper systematically reviews the effects of the α-Mg matrix phase on mechanical properties (e.g., when the average grain size of pure Mg is refined from 59.7 µm to 1.57 µm, the alloy’s yield strength increases by 122 MPa), corrosion resistance (e.g., adding 0.5% Gd and 0.5% Sc to pure Mg reduces the alloy’s weight loss rate from 208.71 mm/year to 0.29 mm/year), damping properties, electromagnetic shielding properties, and flame retardancy, and reveals the microscopic interaction mechanisms between the matrix phase, solute atoms, crystal defects, and second phases. Furthermore, this paper critically analyzes the key role of the matrix phase in emerging fields such as bio-Mg alloys (e.g., controlled degradation rate design), Mg-air batteries (e.g., anode efficiency optimization), and Mg-based hydrogen storage materials (e.g., enhancement of hydrogen absorption/desorption kinetics). Finally, this paper explores the significant potential of data-driven methods in the design and development of next-generation high-performance Mg alloys.

The synergistic enhancement of strength and ductility remains an urgently demanded challenge for refractory high entropy alloys (RHEAs). Here, we propose a novel preexisting twinning strategy to achieve excellent strength-ductility synergy. Advanced crystallographic analysis and molecular dynamics simulations reveal that the mechanism of preexisting {112}<111> twinning enhances the ductility via inducing rotational twinning. The rotational twins serve as an effective slip transfer interface and dislocation reaction node, which facilitates the local strain coordination. More crucially, the following rotational twin modes have been identified: {11¯4}<221‾>, {11¯5}<552‾>, {11¯7}<772‾>, {11¯9}<992‾> (rotation around the common <110> pole), and a special {21‾1}<111> mode, in stark contrast to the classical twinning shear mechanism. At 723-823K, preexisting twins trigger early dynamic recrystallization, refine grain structures, and serve as nucleation sites for deformation twins, while atomic kinks along the rotational twin boundaries dynamically drive twin rotation and suppress crack propagation. Consequently, the non-equiatomic TiNbZrHfTa alloy reaches a remarkable yield strength of ∼660±11 MPa with 20.74±1.26% elongation at 723 K, and elongations exceeding 17% at 823 K and 50% at 923 K, respectively, which successfully overcomes the intermediate-to-high-temperature embrittlement problem of RHEAs. Altogether, this work offers a transformative pathway for designing high-performance RHEAs for extreme environments.

Bulk metallic glasses (BMGs) in the Fe-Nb-Y-B system are renowned as soft magnetic materials, with some compositions exhibiting exceptional glass-forming ability (GFA) and high thermal stability. However, their detailed thermal behavior and crystallization kinetics remain poorly understood. This study presents a comprehensive investigation of the thermal properties and crystallization kinetics of the [(Fe-0.Co-7(0).(3))(7)(1).2B24Y4.(8)](9)Nb-6(4) BMG, which has a wide supercooled liquid region (SLR) of 98 K and excellent magnetic softness. Pair distribution function (PDF) and structure factor S(Q) analyses confirm that isochronal annealing at the glass transition temperature (T-g) increases topological ordering and the average coordination number (CN) within the short-range order (SRO), without notably altering the position of the first diffuse maximum in S(Q). An anomalous exothermic event within the SLR was identified and correlated with a further increase in the CN, an increased contribution of (Fe,Co)-Y pairs in the first coordination shell, an improved correlation length, and a reorganization of medium-range order (MRO) cluster connectivity toward vertex-sharing configurations. These changes alleviate topological frustration and result in atomic volume expansion. Concurrently, relaxation at T-g markedly reduces the coercivity (H-c) to 2.3 +/- 0.3 A/m and increases the saturation magnetization (M-s) and Curie temperature (T-c) by 4.5% and 2.5%, respectively. The anomalous exothermic event further optimizes the magnetic properties, achieving a high M-s of 99 +/- 2 Am & sup2;/kg and a T-c of 580 +/- 2 K while retaining low H-c. Non-isothermal crystallization kinetics studied by both isoconversional and isokinetic models reveal a complex two-stage process. The first crystallization event (forming Fe23B6-type crystals) exhibits a more pronounced autocatalytic nature than the second (forming (Fe,Co)(3)B) based on the & Scaron;est & aacute;k-Berggren (S-B) model. Analysis using the Matusita model indicates that the first transformation transitions from an initial self-accelerating, interface-controlled growth to a diffusion-controlled mechanism, accompanied by a continuously increasing local energy barrier (460-560 kJ/mol). In contrast, the second crystallization step proceeds via two-dimensional, interface-controlled growth with a very high initial nucleation barrier (similar to 950 kJ/mol) and subsequently decreasing local activation energy. The average activation energies for the first crystallization event, calculated from the modified Kissinger (691 +/- 10 kJ/mol) and Matusita (725 +/- 7 kJ/mol) models, reflect the exceptionally high thermal stability of this alloy. The underlying mechanisms for these kinetic changes are discussed in detail.

This study investigates the wear behaviors of Inconel 718 (IN718) specimens fabricated by additive manufacturing (AM) and additive-subtractive hybrid manufacturing (ASHM), with a focus on room-temperature milling (RTM) and high-temperature milling (HTM) conditions. The milling process induced severe plastic deformation in the ASHM specimens, resulting in the formation of surface nanocrystalline layers ranging from 10 to 50 mu m in thickness. At room temperature, the wear rates of the RTM and HTM specimens were 4.15 x 10-3 and 4.92 x 10-3 mm3 N-1 m-1, respectively, which were approximately reduced by 33% and 20% compared with the AM specimen. This enhancement is primarily attributed to the increased grain boundary density and the introduction of residual compressive stress. At 650 degrees C, the differences in wear resistance among the specimens diminished, as stable oxide films formed on all surfaces, effectively reducing adhesive wear and mitigating further mechanical degradation.

The inverse proportional relationship between strength and ductility is a well-known paradigm in materials science. Typically, phase and microstructural control are employed to strengthen materials through a homogeneous distribution of reinforcement phases-mostly at the expense of ductility. However, in this study, we report a simultaneous enhancement of both strength and ductility through a localized distribution of fine reinforcements near phase and grain boundaries in spark plasma sintered (SPS) metallic glass powders, originating from the surface treatment of precursor powders. This improves the ductility without a significant loss of strength in centimeter-scale Al-based alloys, even after consolidation at a high temperature of 723 K. This improvement results from the formation of nanoscale oxides transformed from intermediate intermetallic phases through plasma surface treatment of the precursor powders. During the subsequent sintering process, the plasma-treated metallic glass powders become densely packed, producing a locally concentrated distribution of nano-sized reinforcements aligned along the direction of isotropic deformation. Such behavior is not observed for conventionally sintered metallic glass powders without surface treatment.

Bulk metallic glasses (BMGs) in the Fe-Nb-Y-B system are renowned as soft magnetic materials, with some compositions exhibiting exceptional glass-forming ability (GFA) and high thermal stability. However, their detailed thermal behavior and crystallization kinetics remain poorly understood. This study presents a comprehensive investigation of the thermal properties and crystallization kinetics of the [(Fe₀.₇Co₀.₃)₇₁.₂B₂₄Y₄.₈]₉₆Nb₄ BMG, which has a wide supercooled liquid region (SLR) of 98 K and excellent magnetic softness. Pair distribution function (PDF) and structure factor S(Q) analyses confirm that isochronal annealing at the glass transition temperature (Tg) increases topological ordering and the average coordination number (CN) within the short-range order (SRO), without notably altering the position of the first diffuse maximum in S(Q). An anomalous exothermic event within the SLR was identified and correlated with a further increase in the CN, an increased contribution of (Fe,Co)-Y pairs in the first coordination shell, an improved correlation length, and a reorganization of medium-range order (MRO) cluster connectivity toward vertex-sharing configurations. These changes alleviate topological frustration and result in atomic volume expansion. Concurrently, relaxation at Tg markedly reduces the coercivity (Hc) to 2.3 ± 0.3 A/m and increases the saturation magnetization (Ms) and Curie temperature (Tc) by 4.5% and 2.5%, respectively. The anomalous exothermic event further optimizes the magnetic properties, achieving a high Ms of 99 ± 2 Am²/kg and a Tc of 580 ± 2 K while retaining low Hc. Non-isothermal crystallization kinetics studied by both isoconversional and isokinetic models reveal a complex two-stage process. The first crystallization event (forming Fe₂₃B₆-type crystals) exhibits a more pronounced autocatalytic nature than the second (forming (Fe,Co)₃B) based on the Šesták-Berggren (S-B) model. Analysis using the Matusita model indicates that the first transformation transitions from an initial self-accelerating, interface-controlled growth to a diffusion-controlled mechanism, accompanied by a continuously increasing local energy barrier (460–560 kJ/mol). In contrast, the second crystallization step proceeds via two-dimensional, interface-controlled growth with a very high initial nucleation barrier (∼950 kJ/mol) and subsequently decreasing local activation energy. The average activation energies for the first crystallization event, calculated from the modified Kissinger (691 ± 10 kJ/mol) and Matusita (725 ± 7 kJ/mol) models, reflect the exceptionally high thermal stability of this alloy. The underlying mechanisms for these kinetic changes are discussed in detail.

The study of phase-separated metallic glasses (PSMGs) is motivated by both theoretical curiosity and their potential practical applications. It offers important understanding of the atomic arrangement and properties of disordered materials, while also giving new pathways for developing advanced materials with tailored properties. PSMGs exhibit unique structural and physical characteristics that distinguish them from monolithic metallic glasses (MGs), allowing for enhanced mechanical, thermal, and chemical performance. Recent advances in synthesizing PSMGs have paved the way for engineering materials with hierarchical microstructures across multiple length scales, enabling the design of novel composites with optimized strength, ductility, corrosion resistance, and other desirable properties. This chapter presents an in-depth exploration of nanoscale phase separation in MGs, emphasizing its influence on material properties. The discussion is organized into two main units. The first unit provides a brief overview to phase separation in MGs, discussing the underlying mechanisms, microstructural evolution, thermal behavior, and the advantages of phase-separated structures. It also highlights selected findings related to their morphology and properties. The second unit discusses recent advances in Zr-based PSMGs with respect to their design and properties. This also includes the new results of in-situ transmission electron microscopy (TEM) tensile deformation and corrosion tests of phase-separated Zr–Al–Fe–Y MG compositions, which have not been reported so far.

High entropy alloys and metallic glasses represent two classes of metallic materials with unique properties. A composite of them provides an excessive structural space to discover advanced composite materials. In this work, bulk metallic glass-high entropy alloy nanocomposites were successfully fabricated by high-pressure torsion using a multi-sector disk design, with tailored structure and element constitution. The structural evolution is closely linked to the plastic flow and structural state of the individual components. With increasing shear strain, the multi-sector disks experience bonding, layer refinement, and mechanical mixing, finally leading to a nanoscale lamellar structure. As a result of a high level of rejuvenation at the interface, excess free volume is introduced in the metallic glass, promoting alloying with elements from the high entropy alloy and changing the structure of the amorphous phase to a denser state.

In this study crucial mechanical properties for additively manufactured structural materials, namely fracture and fatigue crack growth (FCG) properties, of a Zr-based Vitreloy 105 bulk metallic glass processed by selective laser melting were investigated. For this, compact tension specimens were machined from test cubes with the loading direction parallel to the building direction. The fracture toughness was found to be comparable to values attained from geometry and size independent studies carried out on cast material of the same alloy with values of 27.7 +/- 4.1 MPam1/2. Scatter in the fracture toughness data is linked to intrinsic porosity inside the plastic zone ahead of the crack tip. Also the FCG-resistance is not affected by additive manufacturing and the crack propagation rate is only negligibly raised compared to cast plate material. When the load ratio is raised from 0.1 to 0.7 the crack growth rates, the slope in the Paris regime of 1.7 and the effective threshold Delta Kth,effof 1.21 MPam1/2 remain unaffected. These findings as well as fine and coarse striations found on the fracture surfaces confirm that the governing crack growth mechanism is crack tip blunting and re-sharpening similar as typically found in ductile metallic alloys.

In this study, binary Cu100-xGax alloys were systematically designed to investigate the influence of Ga content and microstructural evolution on the mechanical properties and chromatic tunability of Cu-based alloys. The as-cast alloys exhibited two kinds of microstructural features: i) stable single alpha-Cu solid solution alloys (x <= 13 at%) and ii) dual-phase alloys (15 <= x <= 19 at%) consisting of alpha-Cu and zeta '-Cu3Ga phases. The as-cast dual-phase alloys were subjected to solution treatment at 620 degrees C for 1 h followed by quenching, which formed supersaturated singlephase alpha-Cu alloys (15 <= x <= 19 at%). The chromaticity of alloys characterized via CIE L*a*b* coordinates was significantly influenced by the Ga content as well as the microstructural evolution. The positive a* (redness) gradually decreased in both as-cast singleand dual-phase alloys with increasing Ga content. However, b* in single-phase alloys almost linearly increased with increasing Ga content up to 19 at%, whereas an increasing volume fraction of zeta ' phase in the dual-phase alloys led to the sudden decrease in b*. Moreover, both supersaturated single-phase and dual-phase alloys with high Ga content revealed distinguishable chromaticity, even though the alloys were in identical alloy compositions. The Vickers hardness of the Cu-Ga alloys increased linearly in both stable and supersaturated single-phase alloys up to 112 HV via solid-solution hardening and further increased up to 121 HV in the dual-phase alloys via second phase hardening. This study demonstrates the feasibility of designing the Cu-based alloys with tunable chromaticity and mechanical properties by adjusting microstructural evolution.