Abstract:Lightweight high-entropy alloys (LWHEAs) represent a promising class of materials for advanced structural applications. However, achieving precise control over their phase formation and mechanical properties remains a significant challenge. Although the conventional empirical parameters (mixing enthalpy ΔH_mix, valence electron concentration, atomic size mismatch δ, and electronegativity difference Φ) provide general guidance for phase stability in Ti-Al-based LWHEAs, their predictive accuracy is restricted. The Al/Ti atomic ratio (γ, namely Al/Ti ratio) is a more decisive and precise criterion for microstructure control. Guided by this parameter, a series of Ti_(50–x)Al_(6.5+x)V_11.5Nb_14.5Zr_17.5 alloys were designed and synthesized. Results reveal that γ critically governs the precipitation, extent of short-range ordering, and grain refinement of B2 phase. Additionally, a moderate γ value of approximately 2.0 (Ti₄₆Al_10.5 alloy) yields an optimal synergy of high yield strength (>1 GPa) and considerable tensile ductility (>20%), whereas excessively high γ leads to embrittlement. This work considers γ as a key compositional parameter and provides a practical framework for designing high-performance LWHEAs through integrated parametric and element-ratio control.

Abstract:FeCrMoBC bulk metallic glasses (BMGs) were synthesized via spark plasma sintering (SPS) technique, and subsequent heat treatment was applied to optimize their properties. The effects of annealing on the microstructure, mechanical behavior, and corrosion resistance of the Fe-based BMGs were investigated. Results show that under optimized SPS parameters (sintering temperature of 560 °C, consolidation pressure of 550 MPa, and holding time of 1 min), the as-sintered sample achieves a relative density of 94.40% and a compressive strength of 678 MPa. After heat treatment at 550 °C for 20 min, an amorphous matrix with enhanced mechanical properties can be obtained: the compressive strength increases to 884 MPa, accompanied by superior corrosion resistance, which is characterized by corrosion potential (E_corr) of -0.318 V, corrosion current density (I_corr) of 2.098×10^-7 A/cm², and polarization resistance (R₂) of 59 379 Ω·cm². Notably, annealing at 650 °C for 20 min results in a maximum relative density of 97.23% and a peak microhardness of 758.86 HV, which is attributed to the crystalline phase precipitation and grain refinement. These results demonstrate that controlled heat treatment can effectively improve the densification and comprehensive properties of SPS-processed Fe-based BMGs by regulating the microstructure evolution.

Abstract:Optimal combination of strength and ductility for refractory high-entropy alloys (RHEAs) can be achieved by regulating the alloy composition that induces the mismatch between atomic size and modulus. Thus, the influence of Zr and Ta on the microstructure evolution and room-temperature mechanical properties of Zr_45-xTi₁₅Nb₃₀Ta_10+x (x=0, 5, and 10, at %) RHEAs was investigated. Results show that the variation in the Zr/Ta ratio does not change the phase composition of the alloys. All three alloys are only composed of body-centered cubic phase. However, with the decrease in Zr/Ta ratio, the yield strength and ductility of the alloys are increased simultaneously: the yield strength increases from 901 MPa to 1003 MPa, and the elongation increases from 13.3% to 16.1%. The enhancement in ductility is primarily caused by grain refinement and the decrease in lattice distortion. Meanwhile, the increase in yield strength is mainly attributed to the synergistic effect of the increased shear modulus mismatch induced by the higher Ta content and the grain refinement strengthening. This study provides valuable insights into the influence of composition variation on the properties of RHEAs.

Abstract:The mechanical behavior and microscopic mechanism of the Fe₄₀Mn₂₀Cr₂₀Ni₂₀ high-entropy alloy (HEA) at high/cryogenic temperatures and high strain rates (split Hopkinson bar) were investigated, and relevant theoretical models were used to fit the yield strength and flow stress of HEA. The tensile test results show that HEA exhibits excellent strength-plasticity synergy and excellent work-hardening ability by reducing the temperature or increasing the strain rate. During the dynamic tensile process, the interactions between different forms of dislocations and deformation twins jointly improve the strength and work-hardening ability of HEA. The Zerilli-Armstrong constitutive model was used to predict the temperature sensitivity and strain-rate sensitivity of the yield strength of HEA. At the same time, the Taylor model was used to predict the flow stress change of HEA with the strain rate under dynamic tension, and the model was applied to low-temperature dynamic experiments. The fitting results are consistent with the experimental results, providing a theoretical basis for the subsequent prediction of HEA strength.

Abstract:In-situ ceramic phase-reinforced TaMoTiCr refractory high-entropy alloy (RHEA) composites were prepared by spark plasma sintering with the addition of 2.5wt% and 5.0wt% h-BN, separately. Results show that the h-BN promotes the uniform formation of (Ti, Ta)N, TaB₂, and MoB ceramic phases within the body-centered cubic matrix, significantly increasing microhardness to 1136.95 HV. Tribological test results show that the composite with the addition of 2.5wt% h-BN presents great performance at room temperature with an ultra-low wear rate of 1.64×10^-7 mm³?N^-1?m^-1, while the composite with the addition of 5.0wt% h-BN shows optimal performance at 300 °C. Above 800 °C (elevated temperature condition), lubricious oxide tribolayers, rich in Cr₂O₃, TiO₂, and B₂O₃, form on the material surface, effectively reducing friction and wear. At 1000 °C, the composite with the addition of 2.5wt% h-BN achieves a wear rate of 5.22×10^-7 mm³?N^-1?m^-1. This in situ ceramic reinforcement approach effectively enhances wear resistance of RHEAs across a wide temperature range, offering great potential for advanced aerospace applications.

Abstract:The universal generalizing approach for non-isothermal behaviour of different alloys was provided with the novel deformation modelling. Results show that strong correlation can be found between the predicted model and experiment results, which shows accurate estimation of main applied parameters, such as the linear thermal expansion coefficient. Necking contours and critical thickness at corrugation for ribbon and rod specimens can also be calculated. Fractal analysis of corrugation folds (their main size) was conducted for polycrystalline and amorphous ribbon specimens. Structural peculiarities at the plastic deformation stage were investigated.

Abstract:Molecular dynamics simulations were used to simulate the vapor deposition process for the investigation of the structural evolution of Ni-Nb metallic glasses as a function of substrate temperature. Results show that optimal substrate temperature is approximately 850 K, at which the glass attains the lowest potential energy and thus the highest stability. The formation of ultrastable glass is accompanied by a transition of short-range ordered structure from a distorted icosahedron to a perfect icosahedron. This phenomenon can be further confirmed in Mg-Cu-Y, La-Ni-Al, Zr-Cu-Al, and Cu-Zr metallic glass systems. In this research, the structural origin of ultrastable metallic glass formation is established, providing new insights into the nature of the glass transition.

Abstract:A novel grain structure was developed in a NiCo-based superalloy by short-term annealing and aging treatment. Results show that the novel grain structure consists of residual deformed grains, fine recrystallized grains, and multi-scale L1₂-γ' precipitates. Compared with the conventional heat-treated alloy (yield strength of 1106 MPa; elongation of 18.8%), the alloy with a partially recrystallized microstructure exhibits a significantly higher yield strength of 1371 MPa while maintaining the elongation of 13.3%. This high strength is attributed to synergistic effects from dislocation strengthening (induced by prior cold rolling), fine grain strengthening, and precipitation reinforcement by γ' phases. In contrast, the fully recrystallized alloy demonstrates a yield strength of 1390 MPa and an elongation of 14.3%, primarily due to the uniform fine-grained structure and homogeneously diffused γ' precipitation. The underlying deformation mechanisms are thoroughly investigated, revealing that in addition to precipitates, the dislocation activity, nanotwins, and Lomer-Cottrell locks are also critical for the outstanding mechanical properties. This research provides a practical and cost-effective processing strategy for developing high-performance NiCo-based superalloys for demanding engineering applications.

Abstract:Metallic glasses exhibit exceptional properties but suffer from brittle fracture via shear banding at room temperature. Homogeneous deformation is vital for understanding amorphous plasticity. This review summarized recent advances in homogeneous deformation of metallic glasses in atomic-scale flow mechanisms, evolution of shear transformation zones, flow defects, and hierarchical relaxation processes. The correlation among free volume kinetics, stress-temperature equivalence, and rejuvenation threshold stress was introduced. Role of structural heterogeneity in flow stability was discussed, alongside the application of modern characterization and modeling techniques. The review proposed investigation methods for designing high ductile metallic glasses based on these insights.

Abstract:Metallic glasses are a unique class of materials with exceptional mechanical properties, including high strength, excellent corrosion resistance, and significant elasticity. These materials display intriguing dynamical relaxation processes, which influence their mechanical and thermal properties. Understanding the dynamical relaxations in metallic glasses is crucial for optimizing their performance in various applications. Due to the restrictions of experimental techniques to access processes at the atomic level, the detailed mechanisms responsible for the dynamical relaxations cannot be easily obtained. Numerical simulations are potential candidates to analyze the elementary dynamical processes at the atomic scale and thus to capture the fundamental origin of dynamical relaxations. The development of computing has allowed researchers to reach an enormous advancement in the understanding of the physical mechanisms behind dynamical relaxations in metallic glasses. This review provided a brief overview of the current state of research in numerical simulations of dynamical relaxations in metallic glasses, highlighting key methodologies, significant findings, ongoing challenges, and future directions. By synthesizing current research, this review emphasizes the importance of these simulations in improving the design and processing of metallic glasses (from structural materials to high-performance components) for a wide range of applications.

Abstract:Over the past years, high-entropy metallic glasses (HEMGs) have attracted increasing research interest due to their unique structural characteristics arising from high configurational entropy, as well as distinctive properties such as sluggish diffusion, microstructural heterogeneity, enhanced glass-forming ability (GFA), and improved thermal/mechanical stability. Similar to conventional metallic glasses (MGs), HEMGs lack long-range atomic periodicity; however, the high-entropy effect introduces additional complexity in structural evolution, such as decoupling of the glass transition, potential glass-to-glass transitions, and a continuous polyamorphic transition during reheating. This enables HEMGs with tunable atomic rearrangement, atomic interactions, and chemical/topological heterogeneity, thereby conferring great potential for achieving superior structural and functional properties. Although several review papers have summarized the development of HEMGs, the rapid advancement of this field inspires us to provide a concise overview discussion of the latest research progress in HEMG-forming alloy systems. This review first focused on the GFA of newly developed HEMGs, followed by a comparative analysis of their unusual structural relaxation, crystallization behavior, and mechanical properties relative to conventional MGs. Finally, the unique atomic-scale structure and structural heterogeneity of HEMGs were reviewed, and the review concluded with a summary and outlook.

Abstract:To enhance the amorphous phase content and tribological properties of iron-based amorphous alloy coatings, this study proposed a novel strategy for fabricating copper alloy/amorphous gradient coatings on 45# steel substrate. Using coaxial powder-feeding laser cladding technique, single-layer FeCrMoCBY amorphous coatings and copper alloy (CuSn12Ni2)/amorphous double-layer gradient coatings were separately prepared. The effects of laser scanning speed (2000–4000 mm/min) on the microstructure, amorphous phase formation, and tribological properties of the coatings were investigated. The results show that the copper alloy/amorphous double-layer gradient structure significantly accelerates molten pool cooling via the high thermal conductivity of the copper interlayer, reducing the critical cooling rate requirement for amorphous formation. Consequently, the amorphous phase content is substantially improved to 68.9wt%–92.3wt%, showing a remarkable enhancement compared to the single-layer coating. The highest amorphous phase content (92.3wt%) is achieved at a scanning speed of 3000 mm/min. M₂₃C₆-type carbide submicron crystals precipitate in the coating and are dispersedly distributed in the amorphous matrix, improving the hardness through a pinning effect. The average microhardness of the gradient coating exceeds 1000 HV_0.1 (peak value of 1288.75 HV_0.1, which is six times higher than that of the substrate). It is also found that moderate crystallization can enhance hardness of the material. The wear mechanism of the amorphous alloy coating is dominated by abrasive wear. High hardness leads to brittle spallation and the formation of wear debris, which induces secondary ploughing. This study demonstrates that the gradient structure provides more favorable thermodynamic conditions for amorphous phase formation through the thermal-conductivity regulation effect of the copper alloy interlayer, offering new insights for the engineering application of wear-resistant coatings with high amorphous phase content.

Abstract:The dynamic mechanical relaxation behavior of a Zr₆₀Al₁₀Co₂₀Ag₁₀ metallic glass was investigated by dynamic mechanical analysis, and its thermal stability and crystallization kinetics were further examined by thermal analysis. The results show that the loss modulus of this alloy exhibits a significant broadening α-relaxation peak, and the relatively low activation energy of α-relaxation (3.78±0.21 eV) is associated with the early onset of crystallization. The temperature and frequency dependence of the dynamic mechanical relaxation behavior were analyzed using the Kohlrausch-Williams-Watts (KWW) model, yielding a low Kohlrausch exponent (β_KWW) value that indicates a wide distribution of relaxation time and pronounced dynamic heterogeneity. Using Kissinger equation, the activation energy for the onset of crystallization E_x, the first crystallization peak activation energy E_p1, and the second crystallization peak activation energy E_p2 of this metallic glass are calculated to be 424, 420, and 271 kJ/mol, respectively, suggesting good thermal stability. Crystallization kinetics results show that the first crystallization peak corresponds to a diffusion-controlled process, with an Avrami index =1.97±0.33, which is consistent with the diffusion-dominated growth theory.

Abstract:The elastic modulus of metallic glasses (MGs) is commonly considered to be “inherited” from their solvent (principal) element. However, this rule exhibits significant exceptions in Cu-based MG systems. To uncover the physical mechanism behind this anomalous inheritance, this study selected the Cu-Zr-Hf-Ti system as the research object. Based on first-principles calculations, a multi-scale analysis was conducted, including the macroscopic elastic modulus, atomic-scale bonding characteristics, and the electronic structure. The results show that the elastic modulus of this system is governed by low-stiffness interatomic interactions represented by Zr-Zr and Zr-Ti bonds, rather than by the principal element Cu. Electronic structure analysis further confirms that, although Cu dominates in composition, the electronic density of states (DOS) near the Fermi level is primarily contributed by the d-orbitals of the minor elements Zr and Hf. The introduction of Hf enhances the orbital hybridization between Cu-3d and Hf-5d, and reduces DOS near the Fermi level, thereby significantly increasing stiffness by promoting the directionality and covalency of bonding. Concurrently, the decrease in ratio of bulk modulus to shear modulus (B/G) and Poisson's ratio (ν) values suggests a potential decline in toughness. This work clarifies that the inheritance of the elastic modulus in MGs is essentially determined by the key element that dominates the electronic DOS at the Fermi level. This finding provides a theoretical basis for the rational design of MGs with tailored mechanical properties from an electronic structure perspective.

Abstract:Additive manufacturing technique provides a new approach for the fabrication of complex structures and precise control of the microstructure in high-entropy alloys (HEAs), greatly expanding their application prospects in extreme service environments such as aerospace and deep-space exploration. However, there is still a lack of systematic and in-depth understanding of the mechanical behavior of additively manufactured HEAs under cryogenic conditions, particularly regarding their dynamic impact response and underlying microstructural deformation mechanisms. In this study, a Ni₄₀Co₁₈Cr₁₈Fe₁₄Al₅Ti₅ HEA was prepared using selective laser melting (SLM), and its static tensile and dynamic impact mechanical behaviours at 77 K were investigated. The results show that this HEA exhibits excellent strength-ductility synergy and impact toughness at cryogenic temperature, with a yield strength of 1083.4 MPa, a uniform elongation of 29.8%, and an impact energy as high as 117.7 J. Microstructural analysis reveals that the high-density dislocations, stacking faults, and their interactions between the initial cellular structures during cryogenic deformation effectively facilitate energy dissipation, thereby endowing this HEA with excellent cryogenic impact toughness.

Abstract:The intrinsically sluggish kinetics of the oxygen evolution reaction (OER) severely restricts the practical efficiencies of water splitting and metal-air batteries. In this research, a series of flexible CrFeCoNiMo_x (x=0, 0.2, 0.5, 1) high-entropy alloy (HEA) monolithic electrodes were directly fabricated on carbon cloth by magnetron sputtering, and the influence of Mo doping content on their OER electrocatalytic performance was investigated. The results show that the appropriate Mo doping can significantly enhance the OER activity of the electrode. Among the prepared electrodes, CrFeCoNiMo_0.5 exhibits the highest catalytic activity, delivering a current density of 10 mA/cm² at an overpotential of only 212 mV with a Tafel slope of 37.4 mV/dec. Moreover, the electrode operates stably at 100 mA/cm² for 140 h without noticeable degradation. XPS, TEM and in-situ Raman analyses reveal that Mo doping tailors the electronic structure of 3d metals (Fe, Ni), elevates their oxidation states and promotes surface amorphization/reconstruction, thereby strengthening the adsorption of reaction intermediates. Density functional theory (DFT) calculations further demonstrate that Mo doping optimizes the reaction pathway and lowers the energy barrier for oxygen-vacancy formation. These findings provide both experimental evidence and theoretical support for the application of flexible HEA electrodes in advanced energy-conversion devices.

Abstract:High-performance noble metal electrocatalysts for water splitting face significant challenges including high cost, low atomic utilization, insufficient interface stability, and complex preparation processes, which severely limit their large-scale application. Therefore, developing low-cost, low-energy-consumption, and long-life electrocatalysts for water splitting is urgently needed. In this work, a carbon thermal shock strategy was used to rapidly synthesize ultrafine (10 nm) FeCoNiCrPt high-entropy alloy (HEA) nanoparticles on carbon fibers. Results show that in alkaline medium, the catalyst achieves current densities of 10 mA·cm^–2 for the hydrogen evolution reaction (HER) and 100 mA·cm^–2 for the oxygen evolution reaction (OER) with overpotential of only 34 and 264 mV, respectively. Furthermore, when FeCoNiCrPt samples are used as both anode and cathode in an alkaline electrolyzer for overall water splitting, a current density of 10 mA·cm^–2 is achieved at only 1.53 V, with stable operation for more than 100 h. This carbon thermal shock strategy provides a simple and versatile approach for rapidly synthesizing well-dispersed HEA nanoparticles, offering a new pathway for developing low-cost, highly stable catalysts for overall water splitting.

Abstract:In recent years, industrial dye wastewater like azo dyes has caused severe environmental problems. Metallic glasses (MGs) are considered as promising catalysts for efficient water remediation due to their unique disordered structure, high Gibbs free energy, and excellent corrosion resistance. Ultrasonic pre-treatment was employed to enhance the catalytic performance of Fe₈₁B₁₀Si₉ MG. Results show that the sample treated with ultrasonic energy of 500 J exhibits the optimal reaction rate constant (k_obs) of 1.66 min^-1 compared with the untreated sample. The impact of typical anions (e.g., Cl^-, H₂PO₄^-, NO₂^-, and SO₄^2-) on the methylene blue solution degradation during the Fenton-like process (Fe-MG/H₂O₂) was investigated. With the increase in anion concentration, Cl^-, H₂PO₄?, and NO₂? all inhibit the degradation to varying degrees (k_obs< 0.2 min^-1), whereas SO₄^2- has a relatively weaker effect on the degradation process (k_obs=0.76 min^-1). Using Cl^- as a representative, the synergistic mechanism involved in the process was analyzed. Quenching experiment results indicate that ·OH are the dominant active species, which is synergistically regulated by solution chemistry and surface pathways. The ultrasonic-induced surface morphology reconstruction and valence state regulation enhance the catalytic stability in complex anionic environments. This work provides theoretical guidance for designing and developing high-performance MG catalysts in complex water environment.

Abstract:The introduction of gradient nano-grained (GNG) structure into metallic materials is recognized as an effective strategy to mitigate or eliminate the strength-ductility trade-off. The distribution of grain sizes within the gradient structure plays a critical role in modulating the strength-ductility synergy. In this study, the influences of the gradient grain-size distribution on the mechanical characteristics, strain and strain distributions, dislocation distribution, and grain boundary migration were investigated using molecular dynamics simulations. The results demonstrate that an optimal strength-ductility synergy is achieved when the gradient grain-size range lies within the transition region between the inverse Hall-Petch (IHP) and Hall-Petch (HP) regimes (9.6?19.2 nm). Further analysis indicates that within the IHP-HP transition zone (9.6?19.2 nm), the gradients of local strain and stress are the most pronounced, and the dislocation density reaches a maximum, leading to an optimal balance between strength and ductility. When the gradient grain-size range falls within the IHP softening regime, the plastic deformation is predominantly governed by grain boundary-mediated mechanisms. In contrast, when the gradient grain-size range is located in the HP strengthening regime, dislocation slip becomes the primary mode of plastic deformation.

Abstract:The microstructural evolution and mechanical properties of MoNbVTa_0.5 refractory high-entropy alloy (RHEA) under varying annealing temperatures and holding time were investigated. The results show that microstructural homogenization improves with the increase in annealing temperature at a fixed holding time of 24 h. However, annealing above 1500 °C induces the precipitation of (Nb,Ta)-rich phases, which deteriorates ductility. At 1400 °C, prolonged holding time enhances yield strength, while plastic strain initially increases and then decreases due to the pinning effect of precipitated phases. Notably, the RHEA after homogenization annealing at 1300 °C for 24 h achieves a synergistic improvement in strength and plasticity: the yield strength increases to 1530 MPa, and plastic deformation reaches 9.2%, representing a 58.6% enhancement compared to the RHEA at as-cast state.

Abstract:Refractory high-entropy alloys (RHEAs) usually exhibit high strength but limited plasticity at room temperature. Their strength enhancement depends on the mechanisms such as lattice distortion and solid-solution strengthening, which restrict dislocation motions and thus reduce their plasticity. In contrast, the strengthening mechanisms that improve plasticity often weaken strengthening effect. Therefore, enhancing both strength and plasticity simultaneously remains a significant challenge for RHEAs. To address this issue, TiVZrTaW_x (x=5, 10, 15, 20) low-activation RHEAs were designed and prepared, and the effects of W content on the phase structure, microstructure, and compressive mechanical properties were investigated. The results show that increasing the W content to 10% can enhance both the strength and plasticity simultaneously, and the TiVZrTaW₁₀ RHEA shows a hardness of 535.7 HV, a yield strength of 1808.85 MPa and a plasticity of 7.22%. Such improvement is mainly attributed to the solid-solution strengthening and secondary-phase strengthening effects. To further enhance the mechanical properties, a minor amount of N was added to the TiVZrTaW₁₀ RHEA. The results show that the strength and plasticity of the (TiVZrTaW₁₀)_100?yN_y RHEAs are further improved. The typical (TiVZrTaW₁₀)_98.5N_1.5 RHEA exhibits a hardness of 605.8 HV, a yield strength of 2008.66 MPa, and a plasticity of 11.25%. Through TEM and other analyses, the enhanced mechanical properties are found to mainly result from the secondary-phase strengthening, synergistic deformation of the matrix and secondary phases during compression, and interstitial strengthening effects induced by N addition.

Abstract:TiZrNbHf multi-principal element alloy films were fabricated via magnetron sputtering co-deposition. The phase composition, microstructure, and mechanical properties of the samples were characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), energy-dispersive spectroscope (EDS), and nanoindenter. High-throughput biocompatibility screening of individual composition spots was performed through the construction of discrete biological culture wells. With the aid of machine learning-assisted screening, this work proposed a novel paradigm for designing low-modulus alloys. The results show that the TiZrNbHf multi-principal alloy samples all exhibit a body-centered cubic structure, with Young's modulus and hardness ranging from 15–93 GPa and 1.7–4.8 GPa, respectively. Cytotoxicity tests reveal that optical density values concentrate in the range of 0.75–0.90, demonstrating good biocompatibility. Using a random forest regression model with Ti, Zr, Nb, and Hf as input variables, the influence of each element on Young's modulus was analyzed, revealing that Nb has the most significant effect. By combining Latin hypercube sampling, a predictive dataset was constructed, leading to the design and calculation of three types of low-modulus alloy. This approach provides a theoretical foundation and data support for low-modulus alloy design.

Abstract:High-entropy alloys (HEAs) are emerging alloy materials in recent years, breaking the inherent concept of designing traditional alloy compositions based on 1?2 major elements. Due to their unique structural features and performance advantages conferred by their multi-principal-element combinations, HEAs exhibit wide application prospects in marine engineering. In this review, the basic concepts and development status of HEAs have been introduced. Furthermore, their technological breakthrough, performance features, and corresponding mechanism analysis in different scenarios, including structural mechanics, coating protection, corrosion resistance, radiation tolerance, and component fabrication, have been reviewed. Special attention has been paid to the development status and application scenarios of HEAs in the field of shipbuilding and marine engineering. Some prominent problems currently existing in the research process of HEAs have been summarized, aiming to propose design methods and preparation directions of HEAs. More importantly, it also clarified novel development strategies to solve practical problems such as a series of corrosion and protection issues faced by HEAs under complex service conditions including marine engineering, along with new ideas for the future development of advanced HEAs that possess superior comprehensive performance and enhanced environmental adaptability.

Abstract:Hydraulic machinery serves as the core equipment in hydropower stations and pumping stations, primarily encompassing turbines and pumps. Cavitation and erosion occurring on turbines stand out as the main causes of failure in flow-passing components, which have remained a critical challenge hindering the development of hydraulic machinery for over six decades. Numerous researchers have consistently found that applying a dense coating on the surface of the substrate material can effectively mitigate the damage to hydraulic machinery caused by cavitation and erosion. As an advanced surface modification technique, laser cladding has opened up new avenues for the industrial application of such coatings. By summarizing existing studies, this review comprehensively analyzed the mechanisms, influencing factors, and prediction methods of cavitation and erosion. It specifically summarized the impact of powder composition and operating conditions on the anti-cavitation and anti-erosion performances of laser cladding alloy coatings. Based on the above analysis, the review addressed the current drawbacks of materials in terms of anti-cavitation and anti-erosion performances, summarized the existing problems to date, and outlined the future development directions and trends of laser cladding alloy coatings. This work aimed to provide valuable references for the development of high-performance laser cladding coatings.

Abstract:Ni-based superalloy coatings fabricated by laser melting deposition accumulate a large amount of residual stresses inside the coating, which adversely affects the microstructure and properties of the coating. The grade 4 Ni-based superalloy coatings reinforced with Nb and WC composite were prepared on 304NG stainless steel substrate by laser melting deposition technique, and the residual stresses inside the coatings were reduced by annealing treatment. The effects of annealing temperature and annealing time on the microstructure, microhardness, wear resistance, and tensile properties of the coatings were investigated. The results show that an increase in annealing temperature leads to an increase in the content of the softer matrix phase γ-Ni of the coating, a decrease in hardness, and the transformation of the discretely-distributed eutectic structure into a continuously-distributed network structure. Comprehensive analysis indicates that the coating after 700 °C/1 h/furnace cooling treatment exhibits the most excellent wear resistance and tensile properties. This is because the fatigue cracks generated during friction and wear in this coating disappear, and the wear mechanism transitions from fatigue wear to abrasive wear. At the same time, while ensuring the wear resistance of the coating, the plasticity of the coating is enhanced, achieving a synergistic enhancement of strength and plasticity.

Abstract:Based on eutectic alloy design strategies combined with Pandat thermodynamic calculations, Zr_x(NiFe)_100-x (x=75, 83, 90, wt%) alloy systems were designed and prepared. Furthermore, the intrinsic correlation mechanism between the microstructure and mechanical properties of the alloys was investigated. Results show that at Zr concentrations of 83wt% and above, the alloys exhibit a distinctive lamellar eutectic microstructure (tI12-Zr₂(Ni/Fe)/fcc-Zr) coexisting with hcp-Zr, featuring nanoscale FeZr₃ interphase precipitates at eutectic interfaces. Notably, the liquidus formation temperature exhibits a substantial reduction to approximately 974 ℃. The Zr₈₃(NiFe)₁₇ and Zr₉₀(NiFe)₁₀ alloys exhibit compressive strengths of 1352±12 and 1263±10 MPa with corresponding fracture strains of 14.2%±0.4% and 17.0%±0.3%, respectively. These values represent a significant enhancement in fracture strain compared to conventional Zr-based amorphous alloys while maintaining comparable strength properties. Fractographic analysis reveals that dislocation pinning and shear band bifurcation phenomena induced by eutectic interfaces effectively impede crack propagation, facilitating a transition in fracture mode from brittle cleavage to 45° shear-dominated failure with increasing Zr content. Under dynamic compression, both Zr₈₃(NiFe)₁₇ and Zr₉₀(NiFe)₁₀ alloys exhibit a strain rate hardening effect, and when the strain rate exceeds a critical value, the alloys undergo a ductile-to-brittle transition.

Abstract:The thermal effects of TC4 titanium alloy during laser welding induce microstructural heterogeneity and residual stress in the weld joint, significantly compromising its corrosion resistance. This study investigated the influence of pulsed magnetic field treatment with varying intensities (0.5, 1, 1.5, and 2 T) on the corrosion behavior of welded joints. Results show that magnetic field treatment effectively enhances corrosion resistance, with optimal performance achieved at 1.5 T. Compared to untreated specimen, the 1.5 T-treated specimen exhibits remarkable improvements: polarization resistance (R_p) increases by 13 times, corrosion current density (I_corr) decreases by 30.3%, passivation current density (I_p) reduces by 40.5%, while mass loss rates after HCl immersion for 20 and 40 d decrease by 1.7% and 10.3%, respectively. The decrease in homogeneity index (D-value) of residual stress distribution show a trend of initial increase followed by decrease with ascending magnetic intensity. At 1.5 T, the D-value reduction in x-direction reaches 27.92%, corresponding to optimal energy matching between magnetostrictive effects and dislocation motion. Beyond 1.5 T, magnetostriction saturation induces lattice distortion and dislocation pile-ups, diminishing stress redistribution efficiency. Magnetic treatment facilitates dislocation migration and annihilation, reducing local strain (5.8%?6.9% decrease in KAM_ave) and residual tensile stress (72.0% reduction). This process alleviates stress concentration and decreases the proportion of low-angle grain boundary, effectively releasing type II internal stresses and decreasing corrosion susceptibility. This research proposes an innovative, cost-effective, and eco-friendly post-processing strategy for titanium alloy welded structures.

Abstract:A series of Ni-doped Ni-MoS₂@B-Ti₃C₂ nano-heterostructure electrocatalysts were prepared by in-situ growth of Ni-doped molybdenum disulfide (Ni-MoS₂) via hydrothermal reaction on boron-doped titanium carbide (B-Ti₃C₂, MXene structure) nanosheets as the substrate. The composition, structure, and electrocatalytic hydrogen evolution performance of the catalysts were characterized and evaluated. Results show that the 1%Ni-MoS₂@B-Ti₃C₂ heterostructure outperforms other catalysts with varying Ni contents. In alkaline media, it requires only 130 mV to achieve a current density of 10 mA·cm^-2, exhibits a Tafel slope of 91.8 mV·dec^-1, and maintains stable operation for over 12 h. Theoretical calculations further clarify that Ni doping effectively optimizes the hydrogen adsorption free energy of edge sulfur sites toward zero, which, combined with the strong electronic interaction of the MXene substrate, synergistically reduces the energy barrier for the hydrogen evolution reaction.

Abstract:To meet the high-performance requirements of copper/stainless steel composite materials for the “double-box lap joint structure” in nuclear fusion devices, explosive welding was employed to fabricate thick TU0/316L clad plates. The interface characteristics and their correlation with performance were investigated through microstructural characterization and mechanical testing. Results show that jet interference and wave impedance differences under explosive impact induce a periodic wavy interface (with wavelength of 789 μm). Molten mixing dominates in wave crest regions while solid-state diffusion prevails in trough regions, with deeper diffusion observed in troughs. Dynamic recrystallization occurs in TU0-side grains, whereas 316L-side grains refine to submicron scale. The interface achieves remarkable shear strength (210 MPa) and pull-off strength (230 MPa), both exceeding the ultimate strength of copper matrix. Bend testing shows no interfacial delamination, confirming superior peeling resistance. This research provides critical insights for interface design and process optimization of composite components under extreme nuclear fusion conditions.