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• A novel dual-nanoprecipitation of intragranular "B2+κ′-carbides" strengthened austenitic lightweight steel is designed by coupling the pre-cold rolling and two-step aging process. • Typical K-S and N-W orientation relationships between the austenite matrix and intragranular B2 particles are confirmed. • Pre-cold rolling process effectively promotes the heterogeneous nucleation of B2 particles by introducing dislocations. • The balance of strength-ductility is enhanced via the nanoscale "planar slip and dislocation bow-out" multiple deformation mechanisms. Strength-ductility trade-off is usually an inevitable scenario in κ′-carbides strengthened austenitic lightweight steel. The reduction of ductility is primarily attributed to the shearing of coherent κ′-carbides by dislocations, resulting in strain localization and ultimately leading to a low work hardening rate. Semi-coherent B2 particles, on the other hand, effectively enhance the work hardening capability due to the non-shearable feature. However, achieving a large volume fraction and uniform distribution of B2 particles within the austenite matrix, as well as optimizing their morphology as fine particles, remains a challenge for austenitic lightweight steel. In this study, we have addressed the above challenges by implementing the two-step aging process combined with pre-cold rolling process. The pre-cold rolling treatment, performed prior to the initial aging treatment at 900 °C, effectively promotes the heterogeneous nucleation of B2 particles by introducing dislocations, resulting in a more uniform distribution of B2 particles and a refinement in size (with an average length of 200–500 nm and a width of 50–80 nm). Furthermore, these intragranular B2 particles exhibit the typical K-S and N-W orientation relationships with the austenite matrix. Subsequently, after the second-step aging process at 450 °C, spherical nano-sized κ′-carbides (5 nm) are homogeneously dispersed within the austenite matrix. The above dual nanoparticles provide an approximate precipitation hardening effect of 400 MPa. Concurrently, the nanoscale "planar slip and dislocation bow-out" multiple deformation mechanisms contribute to an efficient source of work hardening capability, leading to a beneficial synergy of strength-ductility. This promising strategy is expected to expand the applications of dual-nanoprecipitation austenitic low-density steel in various lightweight structural materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Providing a paradigm to achieve excellent thermal stability of nanoprecipitates. • Elucidating evolution behaviors of hierarchical nanostructure in HEA. • Revealing mutual diffusion barrier mechanism between BCC and L1 2 phases in HEA. High-density coherent nanoprecipitates have been widely introduced into the design of new structural materials to achieve a superior strength-ductility balance. However, the thermal instability of nanostructures limits their fabrication and application. In this study, we investigated the temporal evolution of nanoprecipitates in coherent nanoprecipitation-strengthened Al 0.5 Cr 0.9 FeNi 2.5 V 0.2 high-entropy alloy during isothermal aging. When annealed at 600 °C for more than 100 h, we found that its nanoprecipitates were invariably stable, with no obvious changes occurring in terms of morphology and distribution. The excellent stability was mainly attributed to the restricted state of interface migration and diffusion owing to the hierarchical nanostructure. The Cr-enriched nano-lamellar BCC phase divided the Cr-depleted FCC(L1 2) matrix, forming barriers to long-range diffusion and resulting in a kinetically slow coarsening rate. As the nano-lamellar BCC phase spheroidized as the aging temperature increased to 700 °C, the diffusion barriers were destroyed. Remarkable coarsening occurred after that, which further verified the significant effect of the nano-lamellar BCC phase on the microstructural stability. These results provide a paradigm for designing alloys stabilized via hierarchical nanostructure, achieving good strength-ductility synergy while excellent thermal stability. [Display omitted] [ABSTRACT FROM AUTHOR]

• The competition of bubble growth and re-dissolution was in-situ observed. • The impact of relative concentration ratio of vacancies and helium was studied. • The synergetic effects of Kr and He irradiations on bubbles were investigated. SiC fiber reinforced SiC matrix composites (SiC/SiC composites) are considered as one of the promising structural materials for liquid type breeding blanket in the fusion energy system. The transmutation gas production rate in fusion reactor is significantly higher compared with fission reactors. An innovative method combining in-situ irradiation and TEM observation and MD simulation was utilized to evaluate the synergetic effects of helium and irradiation on SiC/SiC composites. A comprehensive experiment matrix including Kr irradiation, He pre-implantation with sequential Kr irradiation as well as simultaneous dual beam at 1073 K to 16 dpa and 2400 appm He (150 appm/dpa) was performed using 800 keV Kr and 50 keV He ions. With the support of MD results, the impact of relative concentration ratio of vacancies and helium atoms on the bubble evolution was systematically investigated and the corresponding mechanism was further unraveled, which provides the basis of limiting the bubble density in SiC/SiC composites. Additionally, the direct evidence for the competition of irradiation-assisted bubble growth and re-dissolution was in-situ observed in SiC matrix for the first time. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new class of low-activation tungsten-containing W70Cr15V15 (at.%) multicomponent alloy (MCA) is developed and prepared by powder metallurgy. • The W70Cr15V15 alloy exhibits high compressive strength at both room temperature (∼2677 MPa) and high temperature (1100 °C, ∼1496 MPa), predominating most of the tungsten-containing alloys reported before. • Grain growth of this W-Cr-V MCA is significantly suppressed at the high-temperature range from 1200 °C to 1500 °C, indicating exceptional thermal stability at high temperatures. • Such high thermal stability can be mainly attributed to the significant pinning effects from the in-situ formed oxides at GBs, as well as the sluggish diffusion in the MCA. • The present W-Cr-V MCA system is promising for structural materials employed in nuclear reactors, due to its exceptional thermal stability and high yield strength at high temperatures. We developed a novel low-activation, ultrafine-grained W-Cr-V multicomponent alloy (MCA) with excellent thermal stability and desirable high-temperature strength. The as-sintered W 70 Cr 15 V 15 (at.%) alloy was mainly composed of a body-centered cubic (BCC) solid solution matrix with an average grain size of ∼0.45 μm, minor hexagonal close-packed (HCP) phase, and ultrafine oxides at grain boundary (GB) regions. The average grain size of the MCA was < 2 μm after heating at 1500 °C for 1 h, showing a high thermal stability of the microstructure. Accordingly, the estimated grain growth exponent n (∼7) and the corresponding activation energy (∼433 kJ mol–1) of the MCA indicate that diffusion during the grain growth in the present W-Cr-V alloy is dominated by the GB diffusion. Such high thermal stability can be mainly attributed to the significant pinning effects from the in-situ formed oxides at GBs. Besides, the nonequilibrium segregation of Cr and V at GBs also contributes to the thermal stability of the alloy at temperatures of 1200 °C and below. Furthermore, the average high-temperature compressive strength of the alloy was over 1376 MPa at 1100 °C, mainly due to the prominent solid solution and GB strengthening which were still effective at the high temperature. The results indicate that the present low-activation W-Cr-V alloy system with exceptional thermal stability and high-temperature mechanical properties could be a promising candidate for structural materials in future fusion reactors. [Display omitted] [ABSTRACT FROM AUTHOR]

• Doping 0.005 at.% Ce into RHEA has most pronounced effect of grain refinement. • Ce is found to preferentially segregate at grain boundaries (GBs). • BCC band (0.005Ce alloy) transforms to ω-like phase (0.01Ce alloy) at GBs. • 0.005Ce alloy showed optimized ductility (ε f ∼7.25%) and yield strength ∼ 964 MPa. • Balanced strength-ductility in 0.005Ce due to abundant dislocations and kinks. Nb 0.5 TiZrV 0.5 alloy is one of the lightweight refractory high-entropy alloys (RHEAs) and has a great potential to be structural materials. Here, the microstructural evolution at the grain boundaries (GBs), the tensile properties and the deformation mechanism including dislocation and kink evolution of arc-melting (Nb 0.5 TiZrV 0.5) 100- x Ce x RHEAs (at.%, x = 0, 0.005, 0.01, referred to as 0Ce, 0.005Ce and 0.01Ce alloys) at room temperature (RT) were systematically investigated. Ce was found to segregate at GBs and the most pronounced grain refinement effect in the 0.005Ce sample. With the Ce content increased from 0.005 at.% to 0.01 at.%, the Ce concentration at GBs increased from 0.12 at.% to ∼1.17 at.%, subsequently, inducing compositional fluctuation and facilitating transformation of BCC band (V-rich but Zr-poor) to ω-like phase with a non-close-packed hexagonal structure (NCPHS, V- and Zr-rich but Ti-poor) at GBs. The 0.005Ce alloy exhibited the optimized ductility (ε f ∼7.15%) and maintained yield strength of approximately 964 MPa at RT. The better balance of strength-ductility in the 0.005Ce alloy was resulted from synergistic deformation of multiple grains, high fraction (55.6%) of movable edge dislocations and abundant kink bands with the most slip systems. However, deteriorating ductility (ε f ∼2.29%) of the Nb 0.5 TiZrV 0.5 alloy with 0.01 at.% Ce addition was mainly attributed to precipitation of the brittle ω-like phase at GBs. These results may provide theoretical and experimental guidance for design of the advanced RHEAs with high specific strength through doping Ce or other rare-earth elements. [Display omitted] [ABSTRACT FROM AUTHOR]

• The fundamentals of various synchrotron X-ray technique are reviewed. • Case studies of Mg alloys using synchrotron X-ray techniques are summarized. • The dynamic microstructural evolution and mechanisms of Mg alloys are elucidated. • The future research directions of physical metallurgy studies of Mg alloys are highlighted. Magnesium alloys are the lightest metal structural materials owing to their excellent physical and chemical properties. Microstructural evolution in magnesium alloys under the conditions of casting, thermal-mechanical processing, and in-service environment, play an important role in governing their mechanical properties and reliability/sustainability. A synchrotron light source produces high flux, tunable X-ray energy, high resolution, and high coherence X-ray beams, which can realize in-situ dynamic observation of microstructural evolution in a wide range of alloys during the entire processing chain and in simulated service environments. This article reviews the fundamentals of synchrotron radiation characterization techniques (imaging, diffraction, scattering, and fluorescence holography) and state-of-the-art advanced synchrotron characterization techniques on the microstructure evolution mechanism of magnesium alloys. Case studies span a broad range of solidification, deformation, precipitation, fracture and damage, corrosion, and energy storage. Research opportunities and challenges of physical metallurgy studies of magnesium alloys are highlighted for future studies. [Display omitted] [ABSTRACT FROM AUTHOR]

• The introduction of hard and brittle borides into the B2-type RHEAs realizes a multifold increase in plasticity without sacrificing strength. • In the vicinity of borides, the occurrence of chemical order-disorder transition improves the mobility of dislocation, thereby facilitating the plastic deformability. • The existence of stable borides prevents grain coarsening at elevated temperatures by Zener pinning. Refractory high-entropy alloys (RHEAs) exhibit remarkable strengths at elevated temperatures and are hence extremely promising candidates for high-temperature structural materials. However, the RHEAs with ordered superlattice structures generally suffer from poor room-temperature plasticity, which severely hampers their widespread applications. Here, we discovered that the introduction of multicomponent ceramic nanoparticles (MCNPs) into the RHEAs makes the problem alleviative and realizes a multifold increase in plasticity without sacrificing strength. The detailed characterizations show that the improvement originates from the chemical ordering-disordering transition near MCNPs in the B2-ordered RHEAs. This transition promotes the formation of local disordered regions where the mobility of dislocations is significantly enhanced. These regions wrap around MCNPs to form a unique heterogeneous structure, which suppresses the premature microcracks by the boosted dislocation mobility. Simultaneously, the existence of stable MCNPs prevents grain coarsening at elevated temperatures by Zener pinning. These novel alloy-design ideas shed new insights into developing RHEAs with an outstanding combination of strength and plasticity. [Display omitted] [ABSTRACT FROM AUTHOR]

The trade-off between strength and ductility remains a persistent obstacle in the development of advanced structural materials. In the present study, a novel dual-heterogeneous structure with a bimodal grain distribution in both ferrite and austenite phases was fabricated via cold rolling and partial recrystallization annealing on solution-treated 2205 duplex stainless steel (DSS). The processed steel exhibited superior mechanical properties, with the yield strength increasing from 586 MPa to 903 MPa, and the ultimate tensile strength from 796 MPa to 1082 MPa, while maintaining a high total elongation of 35.3 %. Based on in-situ electron backscatter diffraction (EBSD) and scanning electron microscope (SEM) analyses, the microstructural deformation behavior and strengthening mechanisms of the dual-heterostructured 2205 DSS were elucidated. The outstanding combination of strength and ductility was ascribed to the synergistic effects of grain refinement, dislocation strengthening, and hetero-deformation induced (HDI) strengthening. Moreover, the high ductility in DSS was attributed to the co-activation of cross-slip systems in ferrite {110} and {112} along with the single-slip systems in austenite {111}. These findings provide a new strategy for the design and development of high-strength and ultra-high-strength DSSs. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel strategy is adopted to evade the common strength-toughness tradeoff of ultrahigh-strength titanium alloys. • Deformation kinks are intentionally introduced by cold forging prior to conventional cold rolling and aging processes. • The kinks mediate α s -precipitation, resulting in an ultrafine duplex structure within kink interiors while hierarchical α s -precipitates in the external β -matrix. • The aged kinks enhance dislocation activities, promotes uniform plastic strain and impede crack propagation. • The unique aging structure through kinks-mediating endows a simple Ti-V alloy ultrahigh strength as well as considerable ductile and toughness. Titanium alloys engineered in structural applications achieve ultrahigh strength primarily through precipitation strengthening of secondary α -phase (α s) 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 α s -precipitation upon aging. As a result, an ultrafine duplex (α e + β)-structure is formed within kink interiors, while hierarchical α s -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. [Display omitted] [ABSTRACT FROM AUTHOR]

• Hf 6 Ta 2 O 17 encapsulated graphite powders were synthesized using sol-gel method. • Its mechanical and ablation properties were tested as shielding of C/C composites. • The structural superiority and the role of graphite were elaborated in detail. Herein, nanosized Hf 6 Ta 2 O 17 encapsulated graphite flakes were firstly constructed using the sol-gel method, then deposited on the surface of carbon/carbon (C/C) composites by plasma spraying technique to prolong their service span in critical environments. Nanoindentation results affirmed the active influence of graphite flakes on elevating the toughness of the Hf 6 Ta 2 O 17 coating. Besides, after being exposed to the oxyacetylene torch with a peak temperature of about 2000 °C, the sample achieved near zero ablation (0.06 mg/s), meanwhile its porosity and mass ablation rate showed 39.5 % and 60.0 % reduction when compared to pure Hf 6 Ta 2 O 17 sample. During exposure, the external Hf 6 Ta 2 O 17 served as an oxygen barrier for internal graphite flakes, inversely internal graphite flakes provided a "pinning" effect on external Hf 6 Ta 2 O 17 , which accounted for its exceptional ablation performance. This work offers a new insight into the design of surface modification of C/C composites and other high-temperature structural materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Micro-alloying addition of low-Ca (0.5 and 1 wt.%) to Al-5Cu-0.5Mn alloy can improve the ductility by 3 times to 31.1 % at room temperature in the cast state. • After T6 treatment, the strength of the low-Ca micro-alloyed Al-5Cu-0.5Mn is further improved to 343 MPa, without sacrificing alloy ductility and overcome the strength-ductility trade-off. • The addition of trace elements of Ca generated a substantial of ultra-fine eutectic (Al,Cu)4Ca colonies with nano-lamellae. Ultra-fine eutectic can effectively retards crack expansion and coordinates plastic deformation of grains. • After T6 heat treatment, the ultra-fine eutectic phase transforms from lamellar to spherical, which has better coordinated deformation ability and compensates for the plasticity loss caused by matrix strengthening. The strength-ductility inversion relationship of alloys is a persistent challenge in advanced materials design. Al-Cu series cast aluminum alloys that are considered as an exceptionally high-strength light alloy are not exclusive in structural applications due to their inherently poor plasticity. In this work, we employed a squeeze casting technique and Ca microalloying strategy for microstructure modulation to effectively address this difficulty. The addition of low concentrations of Ca (0.5 wt.% and 1 wt.%) elements to the as-cast Al-5Cu-0.5Mn alloy significantly enhances its plasticity by threefold at room temperature. Unexpectedly, even after T6 treatment, which typically compromises ductility for increased strength, the low-Ca micro-alloyed Al-5Cu-0.5Mn exhibited a further increase in its strength without sacrificing its ductility. The low-Ca addition to the alloy generates an ultrafine eutectic colony with a complex "core-shell" structure, which can serve as a carrier for localized stress transfer, effectively distributing the strain uniformly to more grains. Precipitation hardening of α-Al grains and spheroidization of lamellar ultrafine eutectic phases were simultaneously realized in the low-Ca alloy after T6 heat treatment, which resulted in comparable hardness of α-Al grains and eutectic colonies. The synergistic coordination of external strains through extensive strain-hardening induced by slip line and substantial microcrack generation by ultrafine eutectic colonies is evidenced by a series of in situ characterizations of the low-Ca alloys. Therefore, the uniform spreading deformation due to the transfer of strain-hardening effect and the alternating plastic deformation of α-Al grains and ultrafine eutectic colonies are the critical keys to overcoming the strength-plasticity paradox in low-Ca alloys. This study provides a perspective route for Al-Cu system cast aluminum alloys to be utilized as high-strength and tough structural materials. [ABSTRACT FROM AUTHOR]

• Fully dense high entropy (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 ceramics (HEB) via solid pressureless sintering was achieved at 1900 ℃, 200–300 ℃ lower than that reported in the literature. • Mechanical properties of as-obtained HEB ceramics consolidated by pressureless sintering are comparable or even higher than those of counterparts sintered under pressure. • The melting point of HEB was first calculated and it reveals that the melting point of HEB (3359 ℃) is only a little lower than that of HfB 2 (3380 ℃), while using B 4 C as sintering aids, there is a broad temperature window for pressureless sintering of HEB. High entropy boride ceramics have great potential as structural materials serving in extreme environments. However, their applications are limited by the difficulty of sintering. In the present study, dense (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 ceramics with B 4 C additions were prepared through pressureless sintering at as low as 1900 °C. Calculations based on the CALPHAD approach predict that (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 starts to melt at about 3315 °C whilst B 4 C additions reduce the temperature and broaden the temperature region where solid and liquid coexist. Results showed that the introduction of B 4 C could trigger the densification of (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 at a lower temperature and promote their densification significantly. The relative density of samples with 5 wt% of B 4 C additions sintered at 1900 and 2000 °C was 97.7 % and 99.7 %, respectively. While the sintering temperature was further increased to 2100 °C, the liquid phase was reactively formed, leading to the rapid grain coarsening in samples with B 4 C additions. Strengthened by well-dispersed B 4 C grains, the sample with 5 wt% B 4 C sintered at 2000 °C exhibited excellent mechanical properties with the Vickers hardness, flexural strength, and fracture toughness of 21.07 ± 2.09 GPa, 547 ± 45 MPa, and 5.24 ± 0.14 MPa m1/2, which are comparable or even higher than counterparts sintered under pressure. [Display omitted] [ABSTRACT FROM AUTHOR]

• During deformation, stress gradients in CrCoNi alloys lead to the formation of unique inverse dislocation pileups. This is due to elevated lattice friction and stress gradients in the material. • Lowering temperature, increasing loading rates, and introducing chemical ordering promote the formation of these inverse pileups. • Inverse pileups play a crucial role in suppressing dislocation movement, reducing damage at grain boundaries, and mitigating the risk of catastrophic failure. • Dislocation mechanics analysis reveals that dislocation hardening is the dominant factor in plastic deformation of CrCoNi, even when a linear stress gradient is present, with grain boundary strengthening having a limited effect. In this work, we utilize atomistic simulations and dislocation mechanics to explore the formation of inverse pileups in CrCoNi model alloys and elucidate their unique impact on the strength and ductility of multi-principal element alloys (MPEAs). The present atomistic simulations on single crystals reveal that during the deformation of CrCoNi, stress gradients lead to the formation of novel inverse dislocation pileup. We find that this unique dislocation pattern in a confined volume is due to the elevated lattice friction and significant stress gradient present in the material. Furthermore, this phenomenon can be notably promoted by lowering the temperature, increasing the loading rate, and introducing chemical short-range ordering. Additional simulations on bicrystals show that these inverse pileups play a critical role in suppressing dislocation transmission, reflection, and grain boundary (GB) migration. As a result, they effectively mitigate stress concentration and reduce damage accumulation at GBs, lowering the risk of catastrophic failure due to GB damages. In our theoretical analysis, we utilize dislocation mechanics to predict the formation of the inverse pileup and its subsequent strengthening effect, considering scenarios with and without obstacles. Our investigations encompass various lattice frictions and stress gradients. Remarkably, our results shed light on the prevailing impact of dislocation hardening in the plastic deformation of CrCoNi even under the presence of a linear stress gradient, while the contribution of GB strengthening is found to be comparatively limited. These findings provide valuable insights into the deformation mechanisms of MPEAs in general and significantly aid their applications as promising structural materials. [Display omitted] [ABSTRACT FROM AUTHOR]

The growing need for stronger and more ductile structural materials has spurred an intense search for innovative, high-performance alloys. Traditionally, alloys face a pervasive trade-off: high strength often comes at the expense of ductility and vice versa. The advent of high-entropy alloys (HEAs) offering both high strength and ductility has transformed this landscape. In this work, we discuss the deformation mechanisms of HEAs, examine the foundations of the strength-ductility trade-off, and explore approaches for designing HEAs to surmount this limitation. Furthermore, we analyze the factors that govern HEA-deformation performance, which in turn influence the HEA design. We also propose a perspective on future research directions concerning the mechanical behavior of HEAs, highlighting potential breakthroughs and novel strategies to advance the field. [ABSTRACT FROM AUTHOR]

• Two cross-materials transfer learning strategies were presented to predict the creep rupture life of high-temperature titanium alloys. • The transfer learning models improved the predictions greatly compared to the models obtained by straightly applying commonly employed algorithms on high-temperature titanium alloys. • The robustness of the transfer learning models was confirmed by examining their extrapolation capability on test datasets of different size outside training dataset. High-temperature titanium alloys are the key materials for the components in aerospace and their service life depends largely on creep deformation-induced failure. However, the prediction of creep rupture life remains a challenge due to the lack of available data with well-characterized target property. Here, we proposed two cross-materials transfer learning (TL) strategies to improve the prediction of creep rupture life of high-temperature titanium alloys. Both strategies effectively utilized the knowledge or information encoded in the large dataset (753 samples) of Fe-base, Ni-base, and Co-base superalloys to enhance the surrogate model for small dataset (88 samples) of high-temperature titanium alloys. The first strategy transferred the parameters of the convolutional neural network while the second strategy fused the two datasets. The performances of the TL models were demonstrated on different test datasets with varying sizes outside the training dataset. Our TL models improved the predictions greatly compared to the models obtained by straightly applying five commonly employed algorithms on high-temperature titanium alloys. This work may stimulate the use of TL-based models to accurately predict the service properties of structural materials where the available data is small and sparse. [Display omitted] [ABSTRACT FROM AUTHOR]

• A Co-enriched CoCrNiFe based HEA doped with W, Mo, Al, Ti and Nb additional elements was prepared. • A super-high-strength of 2.48 GPa with ∼3.5% elongation was obtained via thermo-mechanical processing. • The heterogenous microstructure is responsible for the HEA enhancement. • The heterogenous microstructure consists of multi-scale precipitates, fine recrystallized grains and recovered grains with HDDs. • CoCrNiFe based HEAs have a large development space to meet the increasing needs for high performance structural materials. In the present work, a Co-rich CoCrNiFe based high entropy alloy doped with some additional elements W, Mo, Al, Ti and Nb was designed and prepared. The heterogenous microstructure, consisting of multi-scale precipitates, fine recrystallized grains and recovered grains with high density of dislocations, was formed in the alloy by thermo-mechanical processing. Tensile yield strength of the alloy can reach as high as 2.48 GPa with ∼3.5% elongation. It was discussed that the LI 2 -γ′ precipitates, the high density of dislocations and grain boundaries play dominant roles in strengthening the alloy. [Display omitted] [ABSTRACT FROM AUTHOR]

• We reviewed the recent progress of various in situ testing rigs compatible with both laboratory and synchrotron radiation X-ray facilities. • Taking metallic alloys and composites as model materials, we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms. • We also discuss the ongoing direction of in situ multi-scale visualization and characterization in advanced materials and structures. Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components. However, previous studies focus on the surface detection because of very limited penetration capacity of nondestructive testing facilities. Here, we review the recent progress of material damage mechanism by various in situ testing rigs that are compatible with laboratory and synchrotron radiation X-ray facilities. Then, taking metallic alloys and composites as model materials, we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms, quantifying crack growth driving forces and crack closure phenomena, and elucidating the strengthening/degrading effects from microstructure and environment on structural material degradation. Finally, we also discuss the ongoing direction of in situ multi-scale visualization and characterization with the development of advanced high-energy X-ray facilities, the improvement of in situ devices and sample environments, the demand of high-throughput tests, and the processing and application of massive test data. [Display omitted] [ABSTRACT FROM AUTHOR]

• The various combinations of glassy-crystal (A/C) laminated alloys consisting of glassy alloys and. • crystallized alloys like shape memory alloys (SMAs) and high entropy alloys (HEAs). • Multiple deformation mechanisms and their positive influences on mechanical properties of A/C alloys. • Some possible disadvantages such as bonding interfaces of A/C alloys have been identified. • Some promising solutions have been proposed to address some reported disadvantages of A/C alloys. The development of new design strategies to create innovative structural materials, refine existing ones, and achieves compatible combinations of strength and plasticity remains a worldwide goal. Promising alloys, such as shape memory alloys (SMAs), bulk metallic glasses (BMGs), high entropy alloys (HEAs), and heterogeneous pure metals such as Cu, have excellent mechanical responses, but they still fall short of meeting all the requirements of structural materials due to specific flaws, such as lack of tensile deformation for BMGs and low yielding strength for HEAs. To address these shortcomings, proposals such as integrating glassy matrices and crystallized alloys, such as HEAs/SMAs, have been suggested. However, these solutions have unresolved issues, such as the challenging control of B2 phase formation in BMG composites. Recently, glass-crystal (A/C) laminated alloys with alternating layers have been reported to exhibit improved mechanical properties and activated work-hardening behaviors, but they still face pressing issues such as bonding interfaces and unknown deformation mechanisms. This review focuses on design routes such as the selection of alloy components and processing techniques, exploration of micro-structural evolution and deformation modes with an increase in strain, and future solutions to address pressing and unsolved issues. These prominent advantages include diversified deformation mechanisms, such as deformation twinning, martensitic phase transformation, and precipitation hardening, as well as tuned interactive reactions of shear bands (SBs) near the A/C interfaces. Thus, this review provides a promising pathway to design and develop structural materials in the materials field community. [Display omitted] Important notice : The glassy-crystal (A/C) laminated alloys combine the heterogeneous and lamellar structures, being similar to that of creatures and human beings. In a similar way, this type of structures in living creatures can be made into designing and developing the A/C laminated structural materials. The promising components for A/C laminated alloys might be the shape memory alloy based BMG composites and HEAs with moderate yielding strength. Figures in the Graphical abstract are cited from the references of [133] (Top Figure) and [10] (Bottom Figure). [ABSTRACT FROM AUTHOR]

• A facile and scalable spray-drying method has been developed to prepare NVCP@C material, which exhibits three stable voltage platforms and manifests a high electrochemical performance (175 mAh g–1). • In-situ XRD reveals that the NVCP@C exhibits solid-solution and two-phase reaction mechanisms during the charge/discharge processes. • Full cells assembled by HC anode and NVCP@C cathode exhibit a long cycling performance (70% after 1000 cycles at 2000 mA g–1). Due to its abundant sodium content and low cost, sodium-ion battery (SIB) has become an effective substitute and supplement for lithium-ion batteries, which has a broad development prospect in large-scale energy storage systems. Na-super-ionic conductor (NASICON) structural materials have stable 3D skeleton structures and open Na+ transport channels, which is a very promising SIB cathode material. But in the typical NASICON material Na 3 V 2 (PO 4) 3 (NVP), the number of electrons involved in NVP per formula unit is less than 2 at the stable voltage window, which limits the further improvement of battery performance. In this work, we report another NASICON structured Na 3 V 4/3 Cr 2/3 (PO 4) 3 @C (NVCP@C), which is obtained by Cr-doped NVP through spray drying. By taking full advantage of the voltage platforms of V5+/4+, V4+/3+, and V3+/2+ in the window of 1.5–4.4 V, NVCP@C delivered a high discharge capacity (175 mAh g–1) and durable cyclability (86% capacity retention for 2000 cycles). In-situ X-ray diffraction results demonstrate that the reversible structural evolution accompanies by solid-solution reaction and two-phase reaction mechanisms co-exist during charge/discharge processes. When coupled with Na+ pre-embedded hard carbon (HC), the assembled NVCP@C//HC full cell delivers a high capacity (105 mAh g–1) and long cycling performance (70% after 1000 cycles). This Cr-doped NVP method offers new insights into the design of high-energy NASICON-structured cathode materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Tripodal piezoelectric device with 600 °C heating function to realize tensile-bending fatigue test. • A modified Coffin-Manson equation based on tensile-bending-thermal combined loading was proposed. • Prediction method of mechanical thermal coupling multiaxial fatigue life with high-accuracy. With regard to the structures subjected to severe mechanical-thermal coupling fatigue conditions, the consistency between service conditions and loading conditions was the prerequisite for the fatigue properties test and fatigue life prediction. A miniature piezoelectric-driven instrument integrating with a tripodal piezoelectric actuator and envelope-type heating function was developed to investigate the mechanical-thermal coupling fatigue properties and obtain the fatigue life of materials under approximate service conditions. A physical model was described to quantitatively calculate the alternating deformation under the mechanical-thermal coupling tensile-bending combined condition. Accordingly, a fatigue life prediction method based on the Coffin-Manson equation under tensile-bending combined loading was proposed to estimate the mechanical-thermal coupling fatigue life in terms of the total coupling deformation and plastic strain amplitude. The feasibility of the proposed instrument was verified through the analysis of displacement responses of high entropy alloy specimens under the thermal-mechanical coupling tensile-bending combined condition at temperatures ranging from RT to 600 °C. The comparison between fatigue lives directly measured through thermal-mechanical coupling experiments and theoretically predicted fatigue lives indicated the availability of the modified Coffin-Manson equation. [ABSTRACT FROM AUTHOR]

[Display omitted] This study provides a comprehensive review of the current research status of fiber reinforced concrete (FRC), specifically focusing on their structural and functional properties and potential applications in the construction industry. The research evaluates the effect of adding different types of fibers, such as steel, glass, and carbon, to concrete on its compressive, tensile, and flexural strength. The study also explores the impact of compacting methods and site conditions on the workability of FRC. In addition, the study examines the functional behavior of FRC, such as the reduction in electrical resistance achieved by adding conductive materials like CNTs, and the use of self-sensing materials for structural control and monitoring. The study also considers the potential of FRC for electromagnetic interference shielding to protect electronic devices from harmful radiation. Overall, the study provides valuable design guidelines for the use of FRC composites in construction projects. [ABSTRACT FROM AUTHOR]

• A novel material structure design strategy combining nacre and foam structures. • Porous nacre/foam ceramics are prepared by a new particle-bubble co-assembly method. • Composite is prepared by new selective infiltration of Al-alloy into porous ceramic. • The composite shows a novel nacre/nanofiber reinforced foam hybrid structure. • The composite exhibits excellent specific strength and specific toughness. Lightweight high-strength and tough composites have enormous potentials in a multitude of fields including biomaterials, sporting goods, aerospace and automobile industries. Herein, we present a strategy to develop a novel bulk Al/SiC composite with a nacre/foam hybrid structure to combine excellent lightweight of foams with outstanding strength and toughness of nacre. To reduce the adverse effect of foam pores on mechanical properties, we further propose to strengthen the foams with 3D nanofiber networks, obtaining a nacre/nanofiber reinforced foam structure. Simultaneously, new particle-bubble co-assembly and selective infiltration technologies are proposed to prepare the novel nacre/foam and nacre/nanofiber reinforced foam structures. The nacre/nanofiber reinforced foam composite shows greater specific strength and toughness than the nacre/foam composite, conventional dense Al/SiC composites and many engineering materials. Our approach opens a promising new avenue for the structure design and manufacturing of lightweight, high-performance structural materials. [Display omitted] [ABSTRACT FROM AUTHOR]