Friction stir welding and its derived solid-state additive manufacturing technologies stand as one of the effective approaches to avoid melting defects and achieve the fabrication of high-performance lightweight alloy components. However，the friction stir welding and solid-state additive manufacturing processes involve complex thermo-mechanical-fluid-microstructure couplings，posing significant challenges to traditional trial-and-error methods for process optimization. The emergence of machine learning provides a transformative solution for process understanding and intelligent control in this field. This paper presents a systematic review of machine learning applications in friction stir welding and additive friction stir deposition. It categorizes and elaborates on the current research status and data processing strategies in aspects such as performance prediction，defect detection，and in-situ control. Addressing the limitations of purely data-driven models，it focuses on investigating different fusion paradigms of physics-informed machine learning and their cutting-edge applications. Finally， it points out that future research should concentrate on further developing generalizable prediction models，achieving real-time closed-loop intelligent control，and integrating active learning for autonomous process exploration，aiming to provide references for advancing these technologies toward intelligent and high-performance development.

Titanium/steel （Ti/Fe） dissimilar metal composite components can fully utilize the advantages of titanium alloys， such as high specific strength， excellent corrosion resistance， and high-temperature stability， while also incorporating the benefits of steel， including high stiffness， low cost， and good machinability. However， the substantial differences in physical and chemical properties between Ti and Fe pose major challenges for the welding of titanium/steel dissimilar metal composites. Due to the advantages of good formability， strong adaptability， and high efficiency， fusion welding joints have garnered significant attention in the field of joining titanium/steel dissimilar metals in recent years. This paper systematically reviews the research progress of laser welding， arc welding， electron beam welding， and other processes， analyses the effects of different fusion welding processes， interlayers， and metallurgical products on the microstructure and properties of joints， and reveals the intrinsic relationship between process-microstructure-properties. Based on this analysis， the existing problems and future research directions of titanium/steel welding technique are summarized， such as the process improvement can not avoid the problems of intermetallic compounds， the limitations of single metal interlayer， and the complexity of composite interlayer scheme. The future research directions， such as metal high entropy alloying， machine learning aided design， and multi-process coordination are proposed to provide technical and theoretical support for the breakthrough of titanium/steel high-quality welding technique and speed up the engineering application process of titanium/steel composite components.

Fiber reinforced polymer （FRP） composites offer advantages such as lightweight construction， high specific strength， fatigue resistance， and corrosion resistance， making them widely applicable in aerospace， rail transit， and other sectors. However， internal damage that occurs during service is often concealed， posing potential safety risks. The advent of intelligent composite materials presents a promising approach for integrated structural health monitoring while enhancing mechanical properties. This paper introduces the preparation methods for carbon nanotube （CNT） reinforced FRP composites. Building on this foundation， the current state of research regarding CNT applications for structural health monitoring of composite materials is reviewed. This research can be categorized into two main areas： health monitoring using embedded carbon nanotube sensors in basic mechanical specimens and engineering components， and the self-monitoring technology of composite materials. The self-monitoring technology is further divided into two methods： resin matrix modification and fiber grafting. Finally， the challenges of CNT-modified FRP composites in industrial applications and sensor monitoring stability in multi-field coupling environments are reviewed， and the development direction of ‘structure-function’ integration of reinforcement system and health monitoring technology is prospected， so as to promote the key step of intelligent composite materials to industrial scale production.

China’s medium- and long-term space science development program clearly puts forward the major tasks of rapidly promoting deep space exploration and accelerating the construction of a space power. The increasingly complex and extreme thermal environment in space imposes more stringent requirements on spacecraft thermal control systems. Conventional thermal control materials exhibit limited and static thermoregulatory properties， failing to meet evolving performance demands. In contrast， smart thermal control materials can dynamically modulate their physical characteristics in response to external stimuli， thereby enabling smart regulation of spacecraft heat dissipation and insulation capabilities， and significantly improving the precision and energy efficiency of thermal management systems. As a result， smart thermal control technology has emerged as a critical development direction for next-generation spacecraft thermal control systems. This review systematically outlines the research progress of typical smart thermal control materials， including thermochromic and electrochromic materials， their applications in space missions and the key challenges in this field. To enable the widespread application of smart thermal control coatings， future research work should be carried out in the AI-assisted material design， low-cost fabrication， failure analysis and life prediction under space environments， and system integration. These endeavors are of great significance for driving innovation in aerospace thermal control technology， accelerating the iterative upgrading of thermal management systems， and supporting the steady progression of national space strategy.

With the rapid development of next-generation vehicles such as electric vertical take-off and landing （eVTOL） aircraft and electric vehicles （EVs）， there is an urgent demand for efficient energy storage systems that combine high energy density with lightweight characteristics. Multifunctional structural batteries （MSBs）， as a disruptive technology integrating energy storage and structural support， merge these two functions into a single component， thereby offering a novel approach to system-level weight reduction， space optimization， and functional integration. This review outlines the fundamental concepts of MSBs and surveys the primary technical pathways， focusing on two core integration strategies： embedded （physical integration） and intrinsic （chemical fusion） architectures. It provides an in-depth examination of key enabling technologies， including the optimization and modification of carbon fiber electrodes， the development of structural electrolytes， and interface engineering strategies. Recent advances in enhancing electromechanical performance through surface modification and composite-phase construction are summarized. Furthermore， novel structural designs and manufacturing processes are introduced， along with evaluation frameworks based on electromechanical coupling theory and multifunctional efficiency metrics. The review concludes by discussing the persistent challenges in the field. Although further fundamental researchs and technical breakthroughs are required for practical application， MSBs demonstrate significant potential to revolutionize conventional design paradigms.

MXene quantum dots （MQDs），with their excellent photovoltaic and surface-active properties，have shown good potential for application in multidisciplinary fields. In this paper，we systematically discuss MXene quantum dots （MQDs） from four dimensions： preparation process，application scenarios，technological bottlenecks and development paths. The process characteristics and applicability of top-down stripping and bottom-up synthesis are compared and analyzed. The innovative applications in the fields of energy storage and conversion，biosensing and molecular detection，precision medical intervention，environmental governance and information encryption are also discussed. In the future，machine learning-enabled reverse material design will accelerate the development of functionalized MQDs，defect engineering modulation and core-shell heterostructure construction are expected to break through the bottleneck of light absorption，the development of degradable bioelectronic devices will expand the boundaries of clinical applications，and the establishment of a standardized toxicity assessment system is a key prerequisite for medical translation. With the in-depth integration of the materials genome project and flexible electronics technology，MQDs are expected to catalyse subversive technological changes in the fields of intelligent sensing systems，individualized diagnostic and therapeutic devices，and human-machine interaction interfaces，and ultimately build a whole industry chain innovation ecology from basic materials innovation to terminal system integration.

TiAl alloys have become key materials for weight reduction and performance enhancement in aero-engines due to their low density， excellent high-temperature strength， and oxidation resistance. However， their room-temperature brittleness and low damage tolerance have long constrained their engineering applications. This paper systematically reviews the development history of TiAl alloys since the 1970s， covering the evolution of material characteristics， major scientific research programs， and progress in engineering applications. Through successive fundamental research projects， the United States and Europe have systematically addressed critical scientific issues such as casting processes， microstructural control， and property evaluation， laying the foundation for the application of GEnx engine blades. Since the 12th Five-Year Plan period， through systematic development under national science and technology programs such as the National Basic Research Program and the National Key Research and Development Program， China has overcome key technological bottlenecks， including the independent development of high-Nb alloy systems and the near-net shaping of full-scale blades， thereby establishing a complete full-chain technological system. Although TiAl alloy design has now evolved to the third generation， achieving fine-grained microstructures and compatibility with conventional forging， persistent challenges include low room-temperature ductility， high sensitivity of fatigue life to micro-defects and stress concentrations， high fatigue crack growth rate， and high creep elastic elongation. Furthermore， this paper identifies a series of critical challenges facing TiAl alloys from the perspectives of manufacturing processes and engineering service. Addressing these issues will lay the foundation for the reliable application of TiAl alloys in high thrust-to-weight ratio aero-engines.

Discontinuously reinforced titanium matrix composites （DRTMCs） exhibit outstanding properties including light weight， heat resistance， high strength， corrosion resistance， and deformability， holding immense promise for applications in aerospace， marine engineering， and biomedical fields，etc. This work systematically reviews the fabrication，processing，and typical properties and applications of DRTMCs. In terms of fabrication， the advantages and limitations of melting casting， powder metallurgy， and additive manufacturing in densification， reinforcement management， and forming scale are analyzed， and reinforcement architecture design with its strength-ductility synergy mechanisms is elaborated. In terms of processing， the influence of reinforcement alignment and matrix recrystallization during hot working on mechanical properties is discussed， along with constraints in cold deformation such as reinforcement fracture and shear band formation. Challenges in welding and machining arising from reinforcement introduction are identified， and advances in joint strengthening strategies and energy-field-assisted machining are reviewed. Regarding applications， typical properties of DRTMCs are summarized， and industrial cases， including hot-formed large-scale components， cold-formed precision sheets and wires， and near-net-shape powder metallurgy parts， are presented. Finally， key future research directions are proposed， encompassing multi-scale biomimetic architecture design， iterative upgrading of in-situ synthesis processes， deep development of additive manufacturing， synergistic control of cold/hot deformation and heat treatment， innovation in joining and machining technologies， and advancement toward industrial-scale application.

Elastocaloric cooling technology， which relies on the crystal structural phase transformation of Ni-Ti-based shape memory alloys， offers advantages such as high efficiency， energy saving， and environmental friendliness. These advantages establish it as a promising alternative to conventional vapor-compression refrigeration. Large adiabatic temperature changes， high material coefficient of performance， excellent fatigue resistance， and a wide operating temperature window are critical indicators of elastocaloric performance， attaining all of these simultaneously remains challenging. This bottleneck has constrained the practical development of the technology. This review systematically introduces the intrinsic relationships and research progress among the manufacturing processes， microstructures， phase transformations， and elastocaloric properties of Ni-Ti-based shape memory alloys. Firstly， it compares conventional and additive manufacturing processes， analyzing their effects on material microstructures and performance. Secondly， from the perspective of substructural features such as grain morphology， precipitates， and twins， it discusses the mechanism by which the microstructure regulates both the thermoelastic martensitic transformation and the defect-induced strain glass transition. Subsequently， the review elaborates on the primary controlling parameters of the elastocaloric effect across different phase transformation pathways， and summarizes technical approaches to enhance overall cooling performance. Finally， this review outlines future research directions： coordinating thermoelastic martensitic transformation and strain glass transition through process innovation and novel alloy design to achieve synergistic optimization of elastocaloric properties； and combining structural design to further enhance heat transfer efficiency， reduce driving energy consumption， and improve adaptability to operating conditions.

Metal-fiber reinforced resin matrix composites formed by combining metals with fiber reinforced polymers（FRP） represent a new generation of lightweight， multifunctional materials demonstrating significant application potential in aerospace， new energy vehicles， and high-end equipment manufacturing. The interfacial bonding state of this composite is the core factor determining its superior mechanical properties. However， issues such as insufficient wettability between metal and resin matrix， weak chemical bonding interactions， high thermal residual stresses due to differing thermal expansion coefficients， and interfacial debonding failure under thermo-mechanical coupled loads severely limit stress transfer efficiency between cross-scale heterogeneous materials and compromise long-term structural reliability. Interface modification techniques， such as metal surface treatment and functional layer introduction， can significantly enhance the interface bonding strength， stress transfer efficiency， and durability between metals and FRP composites， thereby optimizing the overall performance of composite structures. This paper systematically reviews key technologies and research progress in metal-FRP interface modification and outlines future development trends.