In recent years,artificial intelligence-based computational materials modeling has ad-vanced rapidly,with machine learning potentials(MLPs)emerging as a central research direction.By fitting ab initio reference data into continuous and differentiable functional forms,MLPs retain near-quantum-mechanical accuracy while substantially reducing computational cost.This capability alleviates the limita-tions of ab initio methods in simulations of large-scale systems and long timescales.Consequently,MLPs serve as a critical link between atomistic simulations and macroscopic material property predictions,en-abling new possibilities in computational materials science.This review focuses on the moment tensor po-tential(MTP),which offers an excellent balance between accuracy and computational efficiency.This pa-per provides a systematic overview from three perspectives:theoretical framework,algorithmic optimiza-tion,and practical applications.First,the mathematical foundations and design principles of MTP are ana-lyzed.Next,strategies for improving accuracy and accelerating computation are discussed.Finally,repre-sentative case studies on typical material systems are presented to demonstrate the performance of MTP,and future development directions are outlined.
TiAl alloys are important lightweight materials for aerospace propulsion systems owing to their low density,creep resistance,corrosion resistance,and other properties.Fatigue is the primary fail-ure mode of aeroengine blades.Once a long crack forms in a blade,rapid fracture can occur.The initia-tion and propagation of small fatigue cracks therefore directly determine the service life of blades.Focus-ing on the issue of small fatigue cracks in TiAl alloys,this paper systematically reviews the definition and characteristics of small fatigue cracks and summarizes the mechanisms of crack initiation and propaga-tion in TiAl alloys.In addition,the propagation models of small fatigue cracks,together with their applica-bility and limitations,are discussed.Finally,future perspectives are presented regarding the characteriza-tion of fatigue small-crack initiation and propagation behavior and the development of unified life predic-tion methods for TiAl alloys.
Mo,a trace element in the human body,has attracted increasing attention owing to its ex-cellent mechanical properties,uniform degradation behavior,and favorable biocompatibility.The highlight-ed features make it a promising candidate for various biodegradable medical devices,including cardio-vascular and neurovascular stents,cardiac pacemakers,gastrointestinal anastomotic staples,and wear-able bioelectronic devices.Currently,Mo and its alloys have been developed as industrial materials and are well-established in aerospace,electronics,and chemical engineering.However,research on Mo and its alloys as biomaterials is an emerging field of study and faces several critical scientific challenges.In this review,we highlight Mo's intrinsic material characteristics,summarize traditional manufacturing meth-ods and performance advantages,and outline its degradation mechanisms and biological responses in physiological environments.Furthermore,we propose design strategies for Mo-based biodegradable met-als that consider biodegradability,biocompatibility,and the functional requirements of biodegradable im-plants,focusing on composition,microstructure,plastic deformation,and additive manufacturing.Finally,we discuss the future applications and developmental directions of Mo-based biodegradable metals in the field of biomaterials.
Aluminum matrix composites,due to their high specific strength and modulus,excellent thermal conductivity,and controllable thermal expansion coefficient,show prospective broad applications in aerospace,automotive,and electronic packaging.However,traditional single-scale reinforcements of-ten enhance material strength while reducing plasticity and toughness.This strength-toughness trade-off limits further material development.This bottleneck can potentially be overcome through an approach based on the recently developed"cross-scale synergistically reinforcement"strategy,inspired by the mul-tiscale structures of natural biological materials.By the synergistic combination of micron-and nano-scale reinforcements into multiscale structures,the strategy aims to simultaneously enhance strength,modu-lus,plasticity,and toughness.This paper systematically reviews the research progress on cross-scale synergistic reinforcement in aluminum matrix composites.Additionally,this paper elucidates the design philosophy of cross-scale synergy,discusses the primary material systems,key fabrication techniques,and underlying mechanisms of cross-scale synergistic reinforcement,and outlines future research direc-tions.Finally,this paper aims to provide theoretical guidance for the design and development of high-performance aluminum matrix composites.
Magnesium alloys are widely employed in lightweight applications such as aerospace,transportation,and biomedical devices due to their low density,high specific strength,and good biocom-patibility.Elucidating the dynamic evolution of microstructures during preparation and service is essential for alloy compositional design,processing optimization,and performance enhancement.Synchrotron radi-ation sources,which generate X-ray beams with high flux,high resolution,and high coherence,enable in situ dynamic characterization of microstructural evolution in magnesium alloys throughout the entire pro-cessing chain and under simulated service conditions.This paper briefly overviews the development of in situ sample environment devices at synchrotron facilities worldwide.It also systematically outlines recent research on the microstructural evolution mechanisms of magnesium alloys investigated using this ad-vanced technology,covering solidification,deformation and damage,as well as corrosion and protection.Finally,future directions for the application of synchrotron radiation technology in magnesium alloy re-search are discussed.
Outer space provides unique environmental conditions for investigating the physical and chemical properties of metallic materials,the mechanisms of phase transformation processes,and the regulation of microstructure and performance.In particular,it has considerable scientific significance and application value for the preparation of high-temperature,highly active metallic materials,as well as for the implementation of in situ resource utilization and space manufacturing.This study reviews the main research on metallic materials conducted under space experimental conditions since the 1960s and sum-marizes the materials science experimental platforms and their main functions on the Chinese Space Sta-tion,the International Space Station,and the Mir Space Station.Research progress in aspects such as melt flow,liquid properties,solidification structure,and extravehicular exposure is analyzed.The special phenomena and new laws unveiled through space experiments are clarified.Finally,the research and de-velopment trends of metallic materials for space manufacturing are prospected.
Strain path is a critical factor governing the forming quality of metallic components,includ-ing their geometry,microstructure,and service performance.Achieve high-quality forming often requires the use of nonlinear and complex strain paths,which inevitably give rise to multiscale deformation behav-iors.Understanding and characterizing these mechanisms has therefore become a frontier topic in the field of plastic forming.This review synthesizes recent advances in the investigation of macroscopic me-chanical responses,damage behavior,and microstructural and textural evolutions under complex strain paths,emphasizing the central role of stress path history in shaping multiscale deformation mechanisms.Finite element modeling strategies that account for strain path effects are discussed,including constitutive models,limit prediction and damage models,as well as microstructure evolution models,with particular at-tention to their roles in improving predictive accuracy and process simulation capabilities.Engineering-oriented approaches to strain path design are also summarized,highlighting their potential for optimizing formability and service performance.Finally,perspectives on future research directions are presented.
Extreme environments,such as ultra-high temperatures,extremely low temperatures,and intense irradiation,impose growing demands on structural materials for next-generation engineering appli-cations.Conventional single-principal-element alloys are approaching their performance limits because of insufficient phase stability,low-temperature ductile-to-brittle transitions,and uncontrolled defect evolution.Conversely,high-entropy alloys(HEAs),characterized by multi-principal elements,exhibit high configura-tional entropy,severe lattice distortion,and chemical short-range order.These intrinsic characteristics en-able exceptional thermal-mechanical stability,cryogenic toughness,and irradiation resistance,rendering them promising candidates for applications in extreme environments.Focusing on three representative conditions,this work summarizes the potentials and challenges of HEAs as structural materials,clarifies the underlying high-entropy-driven mechanisms,and identifies key technological barriers.Furthermore,we report perspectives on future research directions and propose pathways to accelerate the transition of HEAs from laboratory-scale research to practical engineering applications.
The topological properties of metallic grain boundaries are crucial in determining their me-chanical,electrical,and chemical behaviors,making them a major focus of grain boundary engineering.This study systematically reviews recent advancements in understanding the topological characteristics of metallic grain boundary structures at various scales,including atomic-scale topological configurations and mesoscale grain boundary network topology.It begins by summarizing current research on the topol-ogy of grain boundary atomic structures,including the coincidence site lattice model,displacement shift complete lattice theory,topological characterisation of grain boundary dislocation networks,and analysis of topological defects.It then introduces characterisation methods for mesoscale grain boundary net-works,emphasising a research framework based on discrete cell complexes and systematically examin-ing the topological properties of these networks.Finally,potential applications of grain boundary topology research in materials design are discussed.
Corrosion fatigue is a typical failure mode of metallic materials subjected to the combined effects of cyclic loading and corrosive environments.It is widely observed in critical fields such as nuclear power,marine engineering,aerospace,and energy equipment,and directly affects the service safety and life assessment of engineering components.With the advancement of advanced energy systems operat-ing in extreme environments such as deep space,deep sea,and deep earth,materials increasingly experi-ence severe environmental-mechanical coupling damage.Among these environments,high-temperature pressurized water,liquid lead-bismuth,and marine conditions represent typical corrosive systems.There-fore,understanding and predicting the corrosion fatigue behavior of metallic materials under these condi-tions is of considerable importance.This paper reviews recent research progress on corrosion fatigue ex-perimental techniques,damage mechanisms,and prediction models for metallic materials in the three representative corrosive environments mentioned above.Regarding experimental techniques,particular attention is given to the development of fatigue testing devices capable of simulating service environ-ments,as well as in situ monitoring methods for specimen strain/displacement and crack length.In terms of damage mechanisms,the competition and synergistic interactions among several mechanisms are dis-cussed,including stress concentration at corrosion pits,rupture of protective films and slip dissolution,hy-drogen ingress and hydrogen-induced damage,and reductions in surface energy.For prediction models,the evolution from traditional empirical models,such as the Basquin and Coffin-Manson models,to data-driven machine learning approaches is summarized.The limitations of current models in terms of engi-neering applicability and integration of physical mechanisms are also highlighted.Furthermore,this paper discusses major challenges in the field,including the lack of experimental techniques for emerging ex-treme environments,insufficient understanding of multimechanism coupled damage theories,and the ab-sence of high-precision life prediction models under small-sample conditions.Future research directions are proposed,including the development of cross-scale in situ characterization techniques,the integra-tion of physical mechanisms with machine learning methods,and the advancement of design and evalua-tion systems for materials resistant to corrosion fatigue.
High-pressure die casting(HPDC),characterized by high filling speeds and rapid solidifi-cation,has become a key manufacturing process for large integrated aluminum alloy structural compo-nents in electric vehicles.However,in large thin-walled castings,complex coupling exists between melt flow behavior and the evolution of microstructural defects,and the underlying mechanisms remain insuffi-ciently understood.This paper systematically reviews recent progress in the fluidity of aluminum alloys under HPDC conditions and establishes a unified analytical framework from three perspectives:process parameters,microstructural characteristics,and analytical models.First,the factors influencing fluidity in die casting are summarized,highlighting that both processing parameters and alloy design jointly affect fluidity by regulating heat transfer and solidification processes.Second,the formation mechanisms of the characteristic layered microstructure in die castings,including the skin layer,defect band,and externally solidified crystals(ESCs),are elucidated.The critical roles of dendritic network connectivity,solute enrich-ment,and pore evolution in flow stoppage are also discussed.Finally,the differences among various ana-lytical models for fluidity are compared in terms of their physical assumptions and predictive capabilities.Overall,the fluidity of die cast alloys is governed by the coupled interactions of thermal,phase transfor-mation,and flow fields.Future research should further focus on the mechanisms of flow stoppage,in situ synchrotron characterization,and data-driven approaches.
Continuous casting is a critical process in the modern iron and steel manufacturing indus-try.The solidification segregation of continuously cast strands largely affects the yield rate,performance,and service life of steel products.National strategic drives have imposed increasingly stringent demands on the requirements for iron and steel materials.So,macro-and meso-scopic segregation in the solidifi-cation of continuously cast strands has become increasingly prominent as the types of alloying elements increase and strand sections continue to be enlarged.This paper elaborates the segregation distribution characteristics in the transverse and longitudinal sections of continuously cast strands and clarifies the formation mechanisms of subsurface segregation,white banding,segregation in the columnar-to-equiaxed transition region,V-shaped segregation,and central/centerline segregation.It also analyzes the generation modes of melt flow and the mechanism of solute segregation cooperatively induced by the melt flow and solidification structure.The paper further identifies the main factors influencing differ-ent types of solute segregation and introduces the technical principles and development status of elec-tromagnetic stirring and mechanical reduction.The importance of refining the solidification microstruc-ture for homogenization control is emphasized.Finally,the paper outlines key research directions for high-homogenization control theories and technologies for ultralarge-section continuously cast strands of high-alloy steels,providing a reference for high-quality continuous casting production of base metals for large structural components.
Ni-based single crystal superalloys are key materials for turbine blades in aero-engines and gas turbines.Their deformation and damage behavior under the coupled effects of high temperature,complex stress states,and harsh environments directly affects blade service safety and lifespan.This pa-per systematically reviews recent research progress on single-crystal superalloys with respect to creep,fatigue,and thermo-mechanical fatigue(TMF),with an emphasis on the evolution of microstructures and damage mechanisms under multifield coupling conditions.For creep,the effects of thickness debit,hot corrosion,and multiaxial stress on material properties are summarized,and emerging phenomena and mechanisms associated with ultra-high-temperature exposure,long-term service,and nonisothermal creep are discussed.For fatigue,the transformation of crack initiation mechanisms under low-cycle,high-cycle,and very-high-cycle fatigue conditions is clarified;the synergistic effects of thermo-mechanical-environment coupling and multiaxial stress are examined;and the critical roles of surface condition and structural characteristics in component fatigue performance are highlighted.For TMF,the influences of phase relationship,crystal orientation,alloying elements,and coating-substrate interactions on damage behavior are reviewed.Additionally,this paper reviews the application and progress of in situ character-ization techniques for elucidating deformation and damage mechanisms.Finally,future research direc-tions in this field are outlined.
Difficult-to-machine metals typically possess unique physical and mechanical properties,such as high-temperature stability,high specific stiffness,and lightweight characteristics.These metals hold strategic significance for high-end equipment sectors such as aerospace,energy and power,and marine engineering.This study systematically reviews the research progress and development trends in the integrated additive manufacturing/hot isostatic pressing(AM/HIP)forming technology for difficult-to-machine metals.The study focuses on the following four typical materials:(i)Be and its alloys,(ii)Ti2AlNb alloys,(iii)nickel-based superalloys with high Ti/Al content,and(iv)metal matrix composites.This study provides an in-depth analysis of the bottlenecks encountered in conventional processing,such as high forming difficulty,low material utilization,and poor microstructural homogeneity.Furthermore,the study highlights key research breakthroughs in the integrated AM/HIP technology,including multiscale HIP sim-ulation,compensation design methods for capsule structures,AM of high-precision and high-density thin-walled capsules,and AM of high-strength soluble ceramic cores.A comparative analysis is performed on the advantages of the technology in the near-net shaping,microstructural homogenization,and perfor-mance optimization of components made from difficult-to-machine materials.Finally,future developments for the technology are outlined,including scientific capsule design,intelligent process control for capsule AM,and synergistic optimization of ceramic core properties.This study provides theoretical support and practical pathways to promote the innovative development of HIP forming technology,expanding its appli-cation in the near-final forming of complex components made from difficult-to-machine metals,and offer-ing technical assistance for the manufacturing of core components in key sectors in China,such as aero-space and defense equipment.
Multiscale plasticity mechanics aims to reveal the plastic deformation response of materi-als across length scales and to establish physical links among the microstructure,deformation mecha-nisms,and macroscopic properties,providing critical insights for materials design and performance opti-mization.Plasticity in metallic materials often involves the interplay of multiple microstructures and defor-mation mechanisms such as dislocations,interfaces,and phase transformations,which together form a highly complex spatiotemporal system.Traditional modeling approaches struggle to handle configuration-al complexity,bridge different scales,or represent the underlying mechanisms in such systems.Recently,machine learning has been integrated with multiscale simulations and constitutive modeling,opening new avenues in multiscale plasticity research.This review focuses on two primary aspects of machine learning-enabled multiscale plasticity studies:multiscale simulations of plastic deformation and the development of constitutive models.Representative examples include machine learning-based interatomic potential con-struction,dislocation dynamics simulations,finite element simulations of crystal plasticity,and data-driven constitutive modeling.Finally,the review envisages future directions for multiscale plasticity mechanics empowered by machine learning.
Dissimilar material joining technologies play a critical role in enabling lightweight design and functional integration in complex structures and are widely applied in aerospace,equipment manufac-turing,and transportation industries.However,significant differences in properties,such as thermal ex-pansion coefficients,melting points,and metallurgical compatibility,pose major challenges.These dispari-ties often result in poor interfacial bonding,the formation of excessive brittle intermetallic compounds,and high residual stresses within joints.This review summarizes major dissimilar material joining tech-niques,including brazing,diffusion bonding,friction stir welding,high-energy beam welding,and additive manufacturing,along with their applications in the fabrication of complex structures.Key scientific issues associated with these processes,such as interfacial bonding mechanisms,joint strengthening strategies,and structural reliability,are discussed,and future development trends are briefly outlined.
Mo and its alloys exhibit considerable potential for aerospace high-temperature components, electronic thermal management systems, and high-temperature power-generation structures due to their high melting point, excellent elevated-temperature mechanical strength, and good creep resistance. However, their application is severely limited by rapid oxidation at temperatures above 700 C-o, where the formation and volatilization of MoO3 lead to accelerated material loss and structural degradation. This oxidation susceptibility can ultimately result in disintegration and catastrophic failure under extreme service conditions. The application of silicide-based coatings is an effective strategy to mitigate high-temperature oxidation by forming a protective barrier that isolates the substrate from the environment. Nevertheless, monolithic silicide coatings often suffer from premature failure caused by thermal expansion mismatch with the substrate and inward silicon diffusion during prolonged high-temperature exposure. In this context, silicide-boride composite coatings have emerged as a promising alternative for further improving oxidation resistance. Despite their potential, the mechanisms governing gradient microstructure formation and the origins of performance variability in such composite coatings remain insufficiently understood. In this study, silicide and silicide-boride composite coatings were fabricated on pure Mo substrates using halide-activated pack cementation, and their microstructural evolution and high-temperature oxidation behavior were systematically investigated. The results demonstrate that B element incorporation promotes the formation of a silicide-boride composite coating with a five-layer graded structure: MoSi2 /(MoSi2 + MoB)/Mo5Si3/MoB/Mo2B. Notably, B facilitates the preferential formation of an initial MoB interlayer at the coating-substrate interface. This interlayer not only inhibits the directional diffusion of Si but also induces a displacement reaction between Si and MoB to form MoSi2 , thereby suppressing the (001) preferred growth orientation of MoSi2 . In addition, volume contraction associated with MoB formation within the MoSi2 + MoB mixed layer generates pores and a roughened interface, which act as high-density nucleation sites and significantly refine the surface MoSi2 grain structure. The refined grain structure accelerated the formation of a dense and continuous SiO2 protective film, thereby effectively inhibiting O diffusion. After 30 h of oxidation at 1200 C-o, the silicide-boride composite coating exhibited an oxidation mass gain of 1.28 mg/cm(2) and an oxidation rate constant of 0.29 mg/(cm(2)& centerdot; h), representing a 53% reduction relative to the silicide coating. Moreover, the MoB interlayer suppressed inward Si diffusion into the substrate, thereby enhancing long-term stability under high-temperature oxidative conditions.
The low electrical conductivity exhibited by CuInTe2, coupled with its relatively high lattice thermal conductivity, results in a suboptimal thermoelectric figure of merit (ZT) and conversion efficiency, thereby hindering its potential for commercial application in the field of thermoelectricity. A series of Al-doped CuInTe(2 )compounds were successfully prepared using solid-state reaction and spark plasma sintering techniques in this study. The influence of aluminum doping on the structure and thermoelectric performance was systematically investigated. Al doping remarkably enhances electrical transport performance by increasing carrier concentration. Meanwhile, Al doping induces substitutional point defects, dislocations, strain fluctuations, and nanoprecipitations of CuInAl4Te8, which act as additional barriers to phonon transport, leading to a reduction in the lattice thermal conductivity. Consequently, a minimum lattice thermal conductivity of 0.72 W/(m & centerdot;K) at 823 K was obtained for CuIn0.8Al0.2Te2 sample, and a maximum ZT value of 0.88, an enhancement of 115% than pristine CuInTe2. The average ZTvalues at 323-823 K and 523-823 K were 0.34 and 0.60, respectively, representing approximately 127% and 122% compared with pristine CuInTe2. The remarkable enhancement of ZT and average ZT values for CuIn1-xAlxTe2 compounds demonstrates the efficacy of In-site doping in CuInTe2.
Interstitial filling with non-metallic small atoms (SAs) provides a crucial pathway for tuning the structure and properties of high-entropy films. Owing to their small atomic size, SAs preferentially occupy interstitial sites and, through their distinct chemical interactions with constituent metallic elements, induce changes in local chemical order (LCO). With increasing SAs content, high-entropy films exhibit a progressive transition from disordered interstitial solid solutions to locally ordered states, and eventually to ordered crystalline or amorphous structures, accompanied by pronounced property variations. Accordingly, this review focuses on high-entropy films and systematically summarizes the effects of SAs filling on crystal structure, LCO, and mechanical, magnetic, and electrical properties. A percolation-theory framework is introduced, in which different LCO types are treated as percolating units with characteristic properties, thereby establishing intrinsic correlations between LCO content and macroscopic property evolution. On this basis, the commonalities and distinctions among different SAs in regulating material properties are summarized and compared. Finally, an outlook on future research directions is provided.
Low-expansion alloys are essential structural-functional materials for advanced technologies requiring stringent dimensional stability. They are key components in precision metrology, electronic and microwave devices, cryogenic systems, and ultraprecision manufacturing equipments, where thermal deformation must be strictly controlled. However, conventional Fe-Ni Invar alloys possess insufficient mechanical strength despite their exceptionally low coefficient of thermal expansion, which limits their applicability in load-bearing environments. Design concept of high-entropy alloys offer a promising pathway to overcome this limitation through multiprinciple element alloy design and the associated synergistic effects. In this work, a novel low-expansion alloy, Al1Cr1(Fe65Co4Ni31)(98), was developed by introducing Al and Cr into the multicomponent system and applying thermomechanical processing to tailor and refine its microstructure. This design strategy aims to achieve the synergistic optimization of thermal expansion behavior and mechanical performance. Additionally, in situ XRD during heating was employed to elucidate the underlying mechanism and monitor phase evolution. After thermomechanical processing, the alloy exhibited pronounced grain refinement and an increased martensite volume fraction of 8.91%. The microstructure further contained abundant deformation twins and a high density of lattice defects, which collectively enhanced the mechanical strength and thermal stability. Within the temperature range of-60 C-o to 100 C-o, the coefficient of thermal expansion decreased to 1.10 & times; 10(-6)-2.04 & times; 10(-6) C-o(-1). In addition to the Invar effect, this ultralow expansion behavior is attributed to the partial compensation of lattice thermal vibrations by the volume contraction associated with martensite reduction during heating, together with the suppression of anharmonic lattice vibrations induced by interfaces and defects. Meanwhile, the refined microstructure delivered an excellent combination of strength and ductility, achieving a yield strength of 324 MPa, an ultimate tensile strength of 452 MPa, and a fracture elongation greater than 20%. Compared with conventional Invar alloys, the designed alloy exhibited a higher specific strength while maintaining a low coefficient of thermal expansion. These results demonstrate that the synergistic optimization of compositional design and thermomechanical processing enables the exceptional integration of low thermal expansion with robust mechanical properties, offering valuable guidance for developing dimensionally stable structural alloys.
