Electrochemical testing techniques，featuring high sensitivity，in-situ real-time monitoring，and multi-scale analysis，have become a core tool for studying corrosion mechanisms and evaluating protective performance of materials. This paper reviews the classification and recent advances of electrochemical testing methods. The characteristics and applicable conditions of traditional and localized electrochemical techniques are analyzed and compared. The role of multi-technique coupling and artificial intelligence data analysis in testing complex corrosion systems and elucidating mechanisms are discussed. The application of electrochemical techniques from the perspectives of corrosion behavior and mechanism research， protective performance evaluation， and online corrosion monitoring are systematically summarized. Finally， it points out that the development of electrochemical testing techniques lies not only in the popularization of single techniques but also in prioritizing the advancement of multi-technique coupling and high-spatiotemporal-resolution in-situ electrochemical characterization， enabling in-depth analysis from the extraction of intrinsic interfacial reaction parameters to the comprehensive understanding of corrosion mechanisms. On this basis，data-driven approaches and intelligent algorithms are integrated to establish quantitative correlations between electrochemical responses and the service life of materials. Furthermore，integrated and lightweight intelligent monitoring systems enable real-time assessment and lifetime prediction under complex engineering conditions，thereby promoting the transition of corrosion electrochemical testing from laboratory-based mechanistic studies to full-life-cycle safety management of engineering materials.

The aircraft landing gear endures complex loads and harsh service environments over extended periods， making it susceptible to various forms of damage. Remanufacturing technology provides an efficient means of repairing such damage and restoring performance， playing a vital role in ensuring flight safety. Focusing on the enhancement of overall performance， the design of both structure and materials has undergone continuous iterations and optimization. Traditional fixed landing gear gradually evolves into lightweight， high-strength retractable systems， while material design philosophies shift from static strength-based approaches toward multi-objective optimization that simultaneously considers damage tolerance， fatigue life， and maintainability. This paper reviews the types， materials， structural composition， typical damage mechanisms， and remanufacturing technologies of aircraft landing gear， emphasizes the typical failure modes and damage mechanisms encountered during service， and systematically summarizes key technological aspects of the remanufacturing process， including precise non-destructive testing and damage assessment， high-energy beam repair and surface strengthening techniques， as well as dimensional restoration and precision assembly repair processes. Furthermore， it highlights future trends such as the application of advanced high-performance materials， intelligent manufacturing technologies， and green remanufacturing processes. This review provides theoretical foundations and technical references for the engineering application and systematic development of aircraft landing gear remanufacturing technologies.

The Bauschinger effect is a classical phenomenon in which metallic materials exhibit a significant reduction in yield stress upon reverse loading after preloading. This review systematically summarizes research advances over the past two decades in microscopic physical mechanisms， responses of advanced materials， constitutive modeling， and engineering control strategies related to the Bauschinger effect. At the microscopic scale， multiscale experimental characterizations have revealed the asymmetric evolution of defect structures （e.g.， dislocation dipoles， dislocation cells， and twin boundaries） under cyclic loading， with such behavior observed in both high stacking-fault-energy metals （such as Al and its alloys， Fe） and low stacking-fault-energy metals （such as brass and austenitic stainless steels）， establishing a quantitative correlation between macroscopic back stress and microscopic defect structures. At the mesoscopic scale， cross-scale coupling of discrete dislocation dynamics and crystal plasticity finite element methods has elucidated the non-local characteristics of back stress and the nature of its heterogeneous intergranular distribution. This review discusses the Bauschinger effect in conventional metals such as aluminum alloys and steel， and focuses on the unique Bauschinger effect behaviors arising from multi-mechanism synergy in high-entropy alloys， magnesium alloys， nanostructured metals， and shape memory alloys. On this basis， the evolution of back stress models from empirical formulas to dislocation-density-based physically-based constitutive models is reviewed， along with constitutive modeling approaches that account for microstructural heterogeneity within the crystal plasticity framework. Furthermore， application strategies of the Bauschinger effect in material forming， fatigue evaluation， and performance-oriented design are summarized， reflecting a shift from passive avoidance to active utilization. Finally， future directions are discussed， including extreme environmental effects， high-throughput effect mapping， multi-physics field coupling， and cross-scale integrated computational platforms.

The creep behavior of the third-generation single crystal superalloy DD9 at 1100 ℃/137 MPa is investigated using high-throughput scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. The results show that the average creep rupture life of the alloy under this condition is 260 h. During the creep process，the γ' strengthening phase exhibits a gradual evolution from an initial cuboidal shape to directional coarsening， rafting， and eventually to local derafting at the later stage of creep. The composition difference between the dendrite core and the interdendritic regions is an important factor affecting the microstructural evolution of the DD9 alloy. The dislocation evolution during creep is characterized by initial dislocation motion mainly within the γ matrix channels， the formation of dense dislocation networks at the γ/γ' interfaces during secondary creep， the shearing of the γ' strengthening phase by dislocation pairs during tertiary creep， and a further increase in the number of dislocations shearing into the γ' phase at the fracture stage.

Ultra-thin metal plate welding presents several formidable challenges， including a high susceptibility to deformation， difficulties in precisely controlling weld depth， and significant fluctuations in joint performance. Traditional welding methods frequently fall short in overcoming these obstacles to achieve high-quality welds. To overcome the limitations inherent in conventional welding processes， the constrained tungsten inert gas （TIG） arc welding technique is adopted. A comprehensive and comparative analysis is conducted on the weld quality and performance of three ultra-thin metals： 304 stainless steel， 5052 aluminum alloy， and T2 copper. Through in-depth metallurgical analysis， the microstructure of the welds is thoroughly examined. Moreover， laser confocal microscopy is utilized to quantitatively characterize the weld morphology and surface roughness. Tensile tests and the four-point probe method are employed to assess the mechanical properties and electrical conductivity of the welds， respectively. The results demonstrate that the constrained TIG arc welding process successfully achieve stable welding for all three ultra-thin metal materials， yielding well-formed welds with relatively excellent mechanical properties. A comparative analysis of the tensile strength of the welded joints reveal that the tensile strength of 304 stainless steel welds can reach 90% of that of the base material， while the tensile strengths of 5052 aluminum alloy and T2 copper welds are approximately 50% of the base material’s. Metallurgical examination show no obvious defects in the welds of 304 stainless steel and T2 copper， but minor undercutting is detected in the 5052 aluminum alloy welds. Conductivity tests indicate only a slight increase in weld resistivity compared to the base material， which still satisfies application requirements. The constrained TIG arc welding process exhibits significant advantages in ultra-thin metal plate welding， with the resulting weld quality and performance effectively meeting the needs of practical applications. This validates the promising application prospects of this process in ultra-thin plate welding and offers theoretical guidance for its practical implementation.

With the swift advancement of fourth-generation nuclear reactors and small modular reactors， the operating conditions for nuclear fuel elements， including temperature and irradiation environment， have become increasingly harsh， which in turn places higher demands on the performance of brazing materials. To promote the high-quality and self-sufficient development of nuclear-grade Ni-based brazing paste， a comprehensive and systematic investigation is carried out on the fundamental characteristics of imported nuclear-grade Ni-Cr-P brazing pastes.The findings reveal that the brazing paste contains 12.7 % （mass fraction， the same below）of a binder that decomposes or volatilizes at temperatures below 300 ℃. The residual amounts of nitrogen， oxygen， and sulfur are less than 0.015%， and the residual amount of carbon is less than 0.055%. The filler powders are spherical particles within the mesh size range of 120-230， composed of a Ni₃P-type compound and a Ni-based solid solution. The filler composition is Ni-13Cr-10.5P， and it has a hardness of（626±23）HV_0.3.When using this paste to braze nuclear-grade 304L stainless steel， the joints mainly consist of a Fe-Ni-Cr solid solution and a Ni₂P-type compound. At room temperature， the joints demonstrate a tensile shear strength of（226±14） MPa and a compressive shear strength of（184±10） MPa. However， the tensile shear strength drops to （130±5） MPa at 350 ℃. All fractures occur within the seam area and exhibit a brittle fracture mode. Under a stress ratio of 0.1 and a stress amplitude of 0.45F_max， the joint shows a fatigue life exceeding 10⁶ cycles.

The application of low heat input and a high cooling rate in the high-speed laser directed energy deposition （HL-DED） process proves advantageous in mitigating the unfavorable residual stresses， deformation， and crystalline grain size issues that are typically induced by conventional laser directed energy deposition （CL-DED）. Nevertheless， a comprehensive understanding of the thermo-mechanical behaviors in both CL-DED and HL-DED processes remains elusive. In this study， a fully-coupled thermo-mechanical model for laser directed energy deposition （L-DED） is developed and experimentally validated. This model takes into account the effects of solid-liquid phase change and the evolution of the gas-liquid interface. A systematic investigation is conducted to explore the influence mechanisms of HL-DED and CL-DED strategies on the geometries of the melt track and heat-affected zone （HAZ）， as well as on temperatures， stresses， and deformations.Under the combined influence of stress relaxation and the melting effect， the residual stresses in the melt track and the substrate phase transformation zone （PTZ） are predominantly determined by thermal contraction during the cooling stage and the constraint imposed by the substrate. The thermal contraction-induced tensile stresses in the melt track and substrate PTZ give rise to a bow-string effect， causing the substrate to warp towards the melt track.Compared with the CL-DED strategy， the temperature field generated by the HL-DED strategy exhibits a lower gradient along the track direction but higher gradients along the transverse and vertical directions. Additionally， the cooling rates during the solidification and phase transformation stages are significantly elevated under the HL-DED strategy. Although the HL-DED strategy leads to higher residual stresses in the melt track and substrate PTZ， along with a more uneven residual stress distribution in the substrate， it results in lower transient stress in the melt track， lower residual stress in the non-PTZ， and significantly reduced substrate deformation.

Focusing on the irradiation service demands of key structural materials in the nuclear power sector， this research delves into the evolution of mechanical properties in 316L stainless steel produced vialaser additive manufacturing when subjected to 3.5 MeV iron ion irradiation. The samples are fabricated using two distinct laser additive manufacturing processes： selective laser melting（SLM） and directed energy deposition（DED）. Subsequently， a comprehensive pre-irradiation analysis is conducted， encompassing microstructural examination， X-ray diffraction（XRD）， and nanoindentation tests under varying doses of iron ion irradiation.Microstructural observations revealed that the SLM samples exhibit fine cellular austenite structures， whereas the DED samples display coarse columnar grains with some ferrite precipitation. XRD analysis demonstrate that both sample types retain austenite as the predominant phase before and after irradiation， with no phase transformation detected， thus indicating their excellent phase stability. The nanoindentation results show that the hardness of the SLM samples increases from 2.81 GPa to 4.33 GPa， representing an approximate 54% rise. In contrast， the hardness of the DED samples rises from 2.70 GPa to 4.10 GPa， equating to an approximate 52% increase. Notably， the DED samples exhibit only a limited hardness improvement （approximately 7.6%） within the dose range of 1-10 dpa， suggesting an earlier onset of hardening saturation. By integrating the analysis with the strain gradient plasticity model， the differences in irradiation hardening under varying doses are clarified.

Elastocaloric refrigeration technology based on shape memory alloys offers high efficiency， energy saving， and environmental protection， making it an ideal alternative to the traditional vapor compression refrigeration technology. Among materials exhibiting the elastocaloric effect， NiTi-based shape memory alloys have become the most promising elastocaloric materials for both scientific research and engineering application， due to their excellent mechanical properties and elastocaloric performance. However， the challenges， such as large stress hysteresis， relatively high transformation stress， and limited cycling stability， hinder largely their commercial applications. This review discusses first the thermodynamic fundamentals and characterization methods of elastocaloric effect， followed by a summary of the recent advancements on enhancing the elastocaloric performance of NiTi alloys through mechanical processing， heat treatment， elemental doping， additive manufacturing， and strain glass， as well as the development of the elastocaloric refrigeration devices and prototypes based on NiTi alloys. Finally， this review discusses the research perspectives， such as the improvement of the material fatigue life， cycling stability and elastocaloric effect by doping elements， microstructure modulation， introduction of strain glass transition， and crystallographic compatibility adjustment； developing new NiTi-based or other alloys with small driving force and large elastocaloric effect； designing and optimizing the material structure to improve the heat transfer efficiency； designing new type of elastocaloric refrigeration devices with high cooling efficiency， long fatigue life， high adaptability of working conditions to broaden their application range.

The rapid development of the aerospace field imposes stringent requirements on elastic materials， which need to simultaneously exhibit light weight， high strength， large recoverable strain， excellent energy dissipation， and fatigue resistance over a wide temperature range. NiTi shape memory alloys are promising candidates due to their superelasticity derived from thermoelastic martensitic transformation. However， limited by their low yield strength and high temperature dependence of superelastic stress， they exhibit a narrow superelastic temperature range， which limits their engineering applications in extreme environments such as aerospace. This paper focuses on NiTi-based alloys with wide-temperature-range superelasticity， systematically reviews the governing mechanisms of the superelastic temperature window， and summarizes the research progress of optimization strategies for expanding the superelastic temperature window， including grain refinement， elemental doping， heat treatment regulation， and composite structure construction. The temperature window expansion efficiency and engineering applicability of each strategy are analyzed. Furthermore， it summarizes the latest frontier applications in the aerospace field and discusses prospective technical pathways for improving material properties as well as potential directions for application expansion. This work aims to provide theoretical reference and technical insights for the high-performance design and engineering application of such materials.