“Heterogeneous structures” or “heterostructures” have emerged as a cutting-edge paradigm in the field of mechanical strengthening and toughening, promising to overcome the long-standing trade-offs among strength, ductility, and toughness in metallic materials. Inspired by the multiscale design principle of natural materials, researchers have proposed a synergistic design of bioinspired “hierarchical lamellar heterostructures”, enabling exceptional and simultaneous enhancements in the strength, ductility, and toughness of metallic materials. This study reviews the theoretical foundations, design principles, and strengthening-toughening mechanisms underpinning several archetypal hierarchical lamellar heterostructures: bionic herringbone type, micro-lamellar heredity pattern, and cocoon-like dislocation network model. This review focuses on how these hierarchical lamellar heterostructures effectively overcome the strength-ductility trade-off limitations imposed by uncontrolled crack propagation, ultrafine grain structures, and high-density dislocations. It also elucidates how this heterostructure strategy and its remarkable efficacy have been successfully extended to multiple metal systems, enabling the design and fabrication of a new generation of key high-speed railway contact wires with internationally leading comprehensive performance. Finally, the review discusses the prospects for developing more advanced hierarchical lamellar heterostructured materials and explores their potential future directions.

Slight variations in the Al content can considerably affect the solidification path of TiAl alloys. Consequently, these variations influence the location of phase regions during the hot deformation process of TiAl alloys. In this study, Ti-(43-45)Al-4Nb-1Mo-0.2B (TNM, atomic fraction, %) ingots were synthesized via arc melting and labeled as 43Al, 44Al, or 45Al depending on their Al contents. Subsequently, TNM sheets were fabricated via hot-pack rolling, and the influence of Al content on the microstructure evolution and mechanical properties of these sheets during the rolling process was systematically investigated.Results indicate that TNM alloys with different Al contents are located in different phase regions when deformed at 1250 ^oC. After preheating for 1 h, the 43Al alloy is mainly composed of equiaxed α/α₂ grains. In contrast, the 44Al alloy exhibits a unique core-shell-like structure with α₂/γ lamellar colonies in the core and α/α₂ grains surrounding it. Compared with the 44Al alloy, the 45Al alloy demonstrates a lamellar structure with larger α₂/γ lamellar colonies. Furthermore, the initial structure remarkably influences the microstructure evolution of TNM sheets during the rolling process and determines the final microstructure composition of these sheets. With increasing Al content, the microstructure of TNM sheets transitions from nearly lamellar to duplex, eventually tending toward a near-γ structure. Additionally, two types of α₂/γ lamellar colonies—newly formed and initially present—are observed in the 43Al and 45Al sheets, respectively. Owing to its unique core-shell-like structure, the 44Al sheet simultaneously contains both types of α₂/γ lamellar colonies. Furthermore, the mechanical properties of TNM sheets with different Al contents were tested at room temperature. Results show a gradual decrease in the tensile strength of TNM sheets with increasing Al content. The 43Al sheet exhibits the best performance, which is attributed to the presence of newly formed lamellar structures. Meanwhile, the 44Al and 45Al sheets develop fractures rapidly because of the increased, clustered, and abnormal growth of equiaxed γ grains or presence of residual α₂/γ lamellar colonies.

As an important metal material, the properties of eutectic alloy are mainly determined by solidification microstructures. The potential control effect of high magnetic field on metal solidification process has been gradually confirmed, making it highly significant to carry out the research on the theory of metal solidification under high magnetic field. In this study, the experiments of directional solidification and quenching of Al-12.7%Si (mass fraction) eutectic alloys without and with a 6 T high magnetic field at various growth velocities were carried out. The effects of the magnetic field and growth velocity on the solidified structures of the alloys and the solute migration behavior were investigated. It is found that with increasing growth velocity the alloy underwent a transformation of a coarsened eutectic to a refined eutectic, and then a hypoeutectic microstructure. While with the same growth velocity, applying a 6 T high magnetic field during the directional solidification process of the alloy could also induce the transformation from a coarsened eutectic to a refined eutectic, and then a hypoeutectic microstructure. The analyses of the quenched solid-liquid interface microstructure and solute distribution suggested that the high magnetic field induced microstructure transformation can be linked to the modification of the solute migration caused by the suppression of the convection by the Lorentz force. The above results indicate that similar with growth velocity, high magnetic field can be another parameter for controlling the solidification microstructures of eutectic alloys.

Ti₂AlNb alloys are a type of lightweight material that has excellent high-temperature performance exceeding that of titanium alloys. Manufacturers often use rolling as a major method to obtain a Ti₂AlNb sheet. After rolling, the mechanical properties of the resulting Ti₂AlNb sheets exhibit evident anisotropy, but the anisotropic mechanism remains unclear. In view of the anisotropic tensile properties of Ti₂AlNb sheets, this study investigates the microstructure, texture, and tensile properties of Ti₂AlNb sheets, as well as to explore the main factors affecting the anisotropy of sheet tensile properties. Results indicate that the microstructure of Ti₂AlNb alloy sheets consists of α₂, B2, and O phases, with each phase exhibiting a strong texture. The B2 phase forms a slightly rotated cubic texture, whereas the O phase develops a distinct <100>//ND (normal direction) phase transformation texture, which is related to the orientation of the α₂ and B2 phases. The α₂ phase exhibits a strong rolling thermal deformation-induced {11\overline{\mathrm{2}}0}<uvtw> texture. The tensile properties of the sheets at room temperature (24 ^oC) and 650 ^oC exhibit remarkable anisotropy, with the transverse tensile strength being higher than the longitudinal strength. However, the longitudinal elongation is higher than the transverse elongation. This result is attributed to the near-T-type strong texture of the α₂ phase and <100>//ND phase transformation texture of the O phase, which make the respective prismatic <a> slip more difficult to activate in the transverse direction of the sheets. As the tensile testing temperature increases to 700 ^oC, the activation of pyramidal <c + a> slip in the α₂ and O phases markedly reduces the anisotropy of the tensile properties.

GH4706 alloy is used for industrial gas turbine disks owing to its excellent properties, including high creep resistance, tensile strength, toughness, and microstructural stability up to approximately 650 ^oC. However, the increasing weight and size of large turbine disks have limited the cooling rate following the solution treatment, which hinders the control of the microstructure and mechanical properties of large GH4706 alloy disks. Herein, four solution post-treatments were conducted on a 1500-mm-diameter disk manufactured from GH4706 alloy after being treated at 980 ^oC for 4 h: air cooling + air cooling (AA), furnace cooling to 825 ^oC and stabilization treatment followed by air cooling (FSA), furnace cooling to 825 ^oC followed by air cooling (FA), and furnace cooling to 825 ^oC followed by asbestos cooling (FAs). The evolution of precipitates during aging (including for γ'/γ" coprecipitation and η phase) and their effects on mechanical properties were analyzed. Results indicated that reducing the cooling rate from 980 ^oC to 825 ^oC promoted the precipitation and growth of the η phase, leading to Ni and Ti consumptions. This inhibited γ'/γ" coprecipitation around the large η phase, thereby favoring the formation of a cellular microstructure. Further reduction in cooling rate from 825 ^oC to 600 ^oC substantially accelerated the growth of γ'/γ" coprecipitates into cubic forms. The volume fractions of the cellular microstructure in the FSA, FA, and FAs treatments were 4.1%, 1.0%, and 1.8%, respectively. The AA and FA treatments had negligible effects on the tensile properties of GH4706 alloy at room temperature; meanwhile, the FSA treatment slightly decreased tensile ductility. The FAs treatment led to a notable reduction in yield strength at room temperature. In impact testing at room temperature, the cellular microstructure accelerated crack initiation and propagation, resulting in a 64% lower impact toughness of GH4706 alloy for the FSA treatment compared to that for the AA treatment. However, during stress rupture testing at 650 ^oC, the cellular microstructure effectively hindered crack propagation and the growth and aggregation of micropores, thereby extending the rupture life. However, the FAs treatment reduced the rupture life due to strength loss caused by the large γ'/γ" coprecipitates. The FA treatment fostered an optimal level of cellular microstructure, thereby increasing the rupture life while maintaining excellent tensile and impact properties at room temperature, demonstrating remarkable overall mechanical properties.

Nickel-based superalloys, known for their excellent high-temperature mechanical characteristics and structural stability, are extensively utilized in critical high-temperature components of gas turbine engines, including combustion chambers, turbine blades, and turbine disks. With the development of aeronautical technology, the required maximum operating temperature of turbine disks is 800 ^oC and above. To meet such high-temperature application requirements, China designed GH4151, a new type of nickel-based wrought superalloy that contains precipitation strengthening elements such as Al, Nb, and Ti along with solid solution strengthening elements such as Cr, Co, Mo, and W. The weight ratio of the solid solution strengthening elements was 34% and that of the precipitation strengthening elements was 10%. Due to the high alloying degree of GH4151 wrought superalloy, its smelting process often results in solute distribution and element segregation between liquid and solid phases, which can lead to the precipitation of numerous harmful phases during solidification, causing cracks in the ingot. Subsequent processing becomes impossible once cracks appear. To study the cast microstructure complexity and its correlation with ingot cracking, the elemental segregation, cast microstructure, phase precipitation behavior, and cracking characteristics of GH4151 wrought superalloy were analyzed by OM, SEM, DSC, extraction phase analysis, XRD, hot compression simulation, and thermodynamic calculations. The results indicated that Nb segregation in GH4151 ingots was severe, with a segregation coefficient as high as 2.3. Elemental segregation in the alloy led to the precipitation of various phases, including massive γ′ phases, Laves phases, MC carbides, γ/γ′ eutectic phases, and η phases. The γ′ phase, Laves phase, and MC carbide structures are Ni_2.42Co_0.40Cr_0.10Mo_0.04W_0.03Ti_0.26Al_0.59Nb_0.12V_0.03, (Co_0.241Cr_0.205Ni_0.554)₂(Nb_0.309Mo_0.242Ti_0.346W_0.102), and (Ti_0.333Nb_0.521Mo_0.100W_0.028V_0.019)C, respectively. Due to elemental segregation, numerous precipitated phases with coarse sizes and irregular morphologies formed during solidification. The GH4151 ingot was highly susceptible to cracking, with potential crack formation at the interface of complex precipitates between dendrites, namely Laves phases, γ/γ′ eutectic phases, MC carbides, η phases, and the matrix. A high γ′ phase content of 41.177% in GH4151 reduced its thermal conductivity and increased the likelihood of thermal stress accumulation during cooling, ultimately leading to increased cracking sensitivity in the alloy ingot due to a combination of solidification segregation and thermal stress accumulation.

W-based alloys play an indispensable role in various fields, such as aerospace and nuclear industries. However, their thermal stability decreases with grain structure refinement, limiting their high-temperature applications. Although certain solute elements can enhance thermal stability through phase separation or grain boundary segregation, a systematic research on the extent of grain structure stabilization and the mechanisms of multicomponent addition is lacking. Herein, ultrafine-grained W-10Cr and W-5Cr-5Sc alloys with uniform grain structures and similar average grain sizes were prepared. The thermal stabilities of these W-based alloys were systematically investigated to elucidate their stabilization mechanisms. Results indicate that sudden grain growth occurs at approximately 1300 ^oC in W-10Cr and W-5Cr-5Sc alloys, representing an increase of approximately 200 ^oC compared with pure W. Kinetic analysis shows that the grain growth index and activation energy for grain growth are minimized at temperatures corresponding to thermal destabilization. Moreover, the grain growth indices of W-10Cr and W-5Cr-5Sc alloys exceed those of pure W during thermal instability. Furthermore, beyond the thermal destabilization threshold, the grain growth rate of the W-5Cr-5Sc alloy was lower than that of the W-10Cr alloy. The addition of Sc modifies the Cr distribution in the alloy. In the W-10Cr alloy, the high-temperature stabilization mechanism of the grain structure was attributed to the precipitation of Cr-rich phases and the segregation of Cr at the grain boundaries. By contrast, the stabilization mechanism in the W-5Cr-5Sc alloy shifts toward the precipitation of Sc-rich phases along with the simultaneous segregation of Cr and Sc at the grain boundaries.

Recent advancements in grain boundary engineering have revealed that the {111}/{111} near singular boundary (NSB) exhibits superior resistance to corrosion attacks than the random boundary in aluminum and its alloys. Thus, understanding the influential factors and formation mechanisms of the {111}/{111} NSB, as well as regulating such boundaries, is crucial for enhancing the resistance performance of aluminum and its alloys against intergranular corrosion attacks. To intrinsically comprehend the formation mechanism of the {111}/{111} NSB in aluminum alloys, this study used high purity aluminum (99.99%) as the experimental material. Initially, the starting samples were synthesized through multidirectional forging at room temperature (25 ^oC), followed by recrystallization annealing at 370 ^oC. The as-synthesized starting samples exhibited uniform microstructures with an average grain size of 20 μm and random grain orientations. Subsequently, two parallel starting samples were rolled at 25 ^oC and at the cryogenic temperature (-196 ^oC), respectively, with an 80% thickness reduction, followed by immediate recrystallization annealing at 370 ^oC for 30 min. Later, a quantitative grain boundary inter-connection characterization method based on EBSD and five parameter analysis was employed to statistically analyze the grain boundary character distributions within the samples. The results revealed that the cryo-rolled and recrystallized sample featured a higher proportion of the {111}/{111} NSB compared to the 25 ^oC-rolled and recrystallized sample. Specifically, the {111}/{111} NSB fraction in the former reached 6.0%, 2.22 times that in the latter. XRD analysis, hardness testing, and EBSD measurements revealed the development of a strong {011}<\mathrm{11}\overline{\mathrm{1}}> deformation texture in the samples rolled at 25 ^oC or the cryogenic temperature. In particular, cryo-rolling was found to impede dynamic recovery; hence, the sample rolled at this temperature featured higher levels of residual compression stress, increased grain fragmentation, and higher stored energy compared to the sample rolled at 25 ^oC. Owing to the higher driving force and more active {011}<\mathrm{01}\overline{\mathrm{1}}>-oriented growth, the cryo-rolled sample formed larger grains and stronger {011}<\mathrm{01}\overline{\mathrm{1}}> recrystallization textures during the subsequent recrystallization annealing. Statistical analysis based on grain boundary tracing demonstrated that the grain boundaries between {011}<\mathrm{01}\overline{\mathrm{1}}>-oriented grains and other oriented grains contained higher proportions of the {111}/{111} NSB compared to the grain boundaries between two randomly oriented grains. Moreover, boundaries between the {011}<\mathrm{01}\overline{\mathrm{1}}>- oriented grains and their diffusive orientations featured notably high proportions of the {111}/{111} NSB. This explains the higher content of the {111}/{111} NSB observed in the cryo-rolled and recrystallized sample than that in the 25 ^oC-rolled and recrystallized sample.

Zirconium alloys are extensively utilized as fuel element materials in water-cooled nuclear reactors owing to their small thermal neutron absorption cross-section, exceptional resistance to high-temperature and high-pressure water corrosion, favorable compatibility with UO₂, and moderate mechanical properties. Loss of coolant accidents (LOCAs) pose a critical risk during the operation of nuclear reactors. During such accidents, the zirconium alloy cladding may be exposed to a mixed atmosphere of air and steam, undergoing high-temperature oxidation that could compromise its structural integrity and threaten nuclear reactor safety. Therefore, understanding the oxidation behaviors of zirconium alloys in high-temperature air-steam environments is essential. This study focused on Zr-0.75Sn-0.35Fe-0.15Cr-xNb alloys (x = 0, 0.15, 0.30, 0.50, and 1.0; mass fraction, %), which were smelted and formed into plate samples. The oxidation behaviors of these alloys in a mixed atmosphere comprising 20% air and 80% steam at temperatures ranging from 800 ^oC to 1200 ^oC were investigated using a synchronous thermal analyzer under simulated LOCA conditions. The microstructure and distribution of N and O in the cross-section of the oxidized samples were examined via OM, SEM, and electron probe microanalysis coupled with wave-dispersive spectroscopy. Results indicate that the effect of Nb content on the high-temperature oxidation behavior of the zirconium alloys is complex and does not directly correlate with changes in Nb content. In general, adding Nb may reduce the high-temperature oxidation resistance of Zr-0.75Sn-0.35Fe-0.15Cr-xNb alloys. The oxidation kinetics curves of the five alloys predominantly follow parabolic-linear or linear laws and display variations with changes in oxidation temperature and Nb content. In particular, oxidation transitions occur at 1000 and 1200 ^oC. In high-temperature steam containing air, the oxidation of zirconium alloys is considerably accelerated by the presence of N₂ and O₂ in air, with N serving as a “catalytic-like” agent, providing new oxidation pathways. The formation and subsequent reoxidation of ZrN contribute to the creation of porous oxide layers, undermining the protective capability of the oxide film. The changing content of Nb during the oxidation process influences the α↔β phase transformation in the zirconium alloy matrix and the monoclinic (m)↔tetragonal (t) phase transformation in the oxide film. Furthermore, Nb tends to increase the O solid solubility in α-Zr, and Nb oxidation promotes cracking of the oxide film, which detrimentally affects the oxidation resistance of the zirconium alloys. Conversely, an increase in Nb content reduces anion vacancy concentration and impedes O diffusion when Nb combines with O, thereby enhancing the oxidation resistance of the zirconium alloys.

With the increasing sophistication of laser additive manufacturing technology, the need for high-performance alloys suitable for additive manufacturing has grown. Developing new alloys with excellent mechanical properties and good formability has become a critical direction in the field of additive manufacturing, but severe defect-like cracking remains a major concern. Based on a new design concept from the corners of the phase diagrams to the central region, multi-principal element alloys (MPEAs, i.e., high-entropy alloys) have introduced new opportunities for the development of high-performance additive manufactured alloys. Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ MPEA (containing 0.02%B element, mass fraction) shows great potential for overcoming the severe trade-off between manufacturability and high strength. On the one hand, Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ MPEA has a yield strength of ~1 GPa and an elongation of ~25%, thus its comprehensive performance is superior to that of most existing MPEAs. On the other hand, because of its slower precipitation kinetics than the IN718 alloy, the main strengthening phase ({\gamma }^{″}) of MPEA is stable at 800 ^oC, and thus it shows promise for eliminating the cracking of the precipitation-strengthened alloys. However, because Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ MPEA is a newly designed alloy, the effects of multi-principal alloying on its non-equilibrium solidification behavior are unknown, as is the mechanism of this effect, and its cracking behavior under additive manufacturing and corresponding mechanism must be evaluated. This work takes Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ MPEA as the research object and uses selective laser melting (SLM) technology and advanced characterization techniques to investigate the crack formation mechanism and control path of the alloy under different SLM process parameters. The formability of Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ alloy under different SLM process parameters was investigated, and the crack formation mechanism of Ni₅₈Cr₂₃Fe₁₀W₅Ti₂Ta₁Nb₁ alloy was revealed. The crack control method was then explored. The results showed that the cracks propagated along the grain boundary of the coarse columnar crystals and preferentially appeared at high-angle grain boundaries (HAGBs). The surface of the cracks presented a smooth and clear dendritic morphology, which is a typical solidification crack. At the terminal stage of solidification, the HAGB regions contain a thin layer of B segregation, which promoted the production of a continuous liquid film, and the liquid film remained stable at HAGB owing to the large grain boundary energy. The residual stress caused by heating/cooling circulation acted on the liquid film and triggered solidification cracking. The relationship between the heat input and the cracking sensitivity was not linear. Cracks cannot be eliminated by simply regulating heat input, and cracks can be suppressed only to a certain extent. The grain boundary density increased, local stress concentration was alleviated, and solidification cracks were successfully eliminated with the addition of TiB₂ nanoparticles.

Maraging stainless steel has extensive applications in aerospace, marine, and other demanding fields because of its high strength. However, its susceptibility to pitting corrosion in Cl^--containing environments considerably limits its practical applications under corrosive conditions. This study investigates the effects of three solution treatments—high temperature solution (HS), low temperature solution (LS), and cyclic low temperature solution (CLS)—on grain size and reversed austenite formation in Cr-Ni-Co-Mo maraging stainless steel. Furthermore, it explores the relationship between its microstructure and corrosion resistance in a 3.5%NaCl (mass fraction) solution. The results revealed that the LS treatment refines the martensite block size from 2.1 μm to 943 nm and increases the reversed austenite content from 1.9% to 7.8% compared with the HS treatment. The CLS treatment introduces a high density of dislocations and retained austenite, which provide favorable nucleation sites and diffusion pathways for elemental redistribution during aging, thereby leading to a substantial increase in reversed austenite content to 33%. Cyclic infiltration corrosion tests and electrochemical measurements confirm that grain refinement and the enhanced reversed austenite content considerably improve the corrosion resistance. Grain refinement increases the density of grain boundaries, facilitates the formation of a passivation film on the surface and reduces susceptibility to intergranular corrosion. Compared with LS-treated steel, CLS-treated steel exhibits a 109 mV_SCE increase in corrosion potential, an 86.25 μA/cm² decrease in corrosion current density, and a 26.82 mV_SCE increase in pitting potential. As the reversed austenite content increases, the total resistance of solution and the passivation film thickness increase, thereby improving the stability and protective performance of the passivation film. Concurrently, pitting charge transfer resistance increases, which improves resistance to pitting corrosion.

Acicular ferrite, renowned for its excellent combination of strength and toughness, has been a focal point of research since the inception of “Oxides Metallurgy” in the 1990s. Researchers have devoted considerable attention to understanding the formation and control mechanisms of acicular ferrite, because it plays a crucial role in refining the austenite grain during the cooling process. In practical applications, acicular ferrite is used in corrosive environment, such as seawater. Therefore, assessing its corrosion resistance performance is imperative. Despite its importance, the corrosion resistance mechanism of acicular ferrite remains somewhat unclear, warranting further investigation to elucidate it and potential corrosion resistance enhancement strategies. Previous studies have paid scant attention to the corrosion resistance performance of acicular ferrite, particularly after tempering. Herein, the seawater corrosion resistance performance of acicular ferrite in the weld metal of high-strength low-alloy steel before and after high-temperature tempering was studied. To understand the effects of tempering temperature and seawater exposure on the corrosion resistance performance of acicular ferrite, the potentiodynamic polarization tests, electrochemical impedance spectroscopy, and potentiostatic polarization tests were performed. Additionally, microstructures and mechanical properties to complement findings were detailed analyzed. Results show that tempering at temperatures of 580, 610, and 640 ^oC for 10 h results in a slight increase in the corrosion potential of acicular ferrite in the weld metal, indicating a weakened tendency of corrosion. As the tempering temperature increases, the corrosion current density decreases substantially, accompanied by an increase in impedance. Moreover, the potentiostatic current density decreases, indicating improved corrosion resistance of acicular ferrite after prolonged high-temperature tempering. Furthermore, the corrosion resistance of acicular ferrite remains considerably stable after tempering. The improvement of corrosion resistance of in acicular ferrite is mainly attributed to the decrease in martensite/austenite (M/A) islands, resulting in a highly homogeneous microstructure that mitigates galvanic couple effects. The observed reduced free energy and potential difference of acicular ferrite further contribute to its improved passivation film formation.

Zr-based amorphous alloys possess excellent glass-forming ability and high energy density, which facilitate the development of new energetic fragments. However, their poor plasticity limits their application in fragment-based systems. This study aims to investigate the Zr-Al-Ni-Cu alloy system by substituting Hf for Cu to examine its effects on the glass-forming ability and mechanical properties of Zr₅₅Al₁₀Ni₅Cu_{30 - x} Hf _x (x = 0, 1, 3, 5, 7, 10, atomic fraction, %) bulk metallic glasses (BMGs). The investigation used XRD, DSC, SEM, and a universal testing machine for characterizing the alloy system. Results demonstrate that moderate Hf substitution for Cu enhances the glass-forming ability, thermal stability, and compressive ductility of Zr₅₅Al₁₀Ni₅Cu₃₀ BMGs. With an Hf content of 7%, the alloy achieves a maximum critical diameter of 12 mm and an expanded undercooled liquid phase interval of 85 K. With an Hf content of 5%, the alloy achieves a critical diameter of 10 mm, an undercooled liquid phase interval of 75 K, and substantially improved compressive plastic strain of 13.3%, thereby enhancing its performance compared with the original composition. Spherical specimens of Zr₅₅Al₁₀Ni₅Cu₂₅Hf₅ with a diameter of 9.4 mm were prepared using vacuum suction casting, followed by quasi-sealed chamber impact overpressure experiments. The results indicate that the critical overpressure velocity of the specimens is approximately 600 m/s, and an impact velocity of 1360 m/s produces a maximum overpressure peak of 0.3291 MPa, where the specimens achieve a peak energy release efficiency of 63.17%.

High-strength aluminum alloys, such as Al-Cu-Li and Al-Zn-Mg, are essential structural materials in aerospace, manufacturing, transportation, and mobile communication owing to their excellent strength-to-weight ratio. However, their use in critical applications is significantly limited by hydrogen embrittlement (HE), a phenomenon in which H atoms interact with microstructural features such as grain boundaries (GBs), leading to irreversible degradation of mechanical properties and potentially catastrophic failures. Despite extensive research, the atomic-scale mechanisms of H trapping at GBs and their detrimental effects on GB cohesion remain unclear, impeding the development of effective anti-embrittlement strategies. This study utilizes first-principles calculations to investigate these issues, aiming to provide a theoretical foundation for anti-embrittlement engineering. The results indicate that H atoms are most stably adsorbed at the short-bridge site on the Al (001) surface, with an adsorption energy of -3.051 eV, and tend to occupy tetrahedral interstitial sites (TIS) in the matrix. The diffusion path of H atoms into the matrix follows the TIS-OIS-TIS mechanism (where OIS denotes the octahedral interstitial site), with significant migration barriers of 0.32-0.56 eV, suggesting a challenge for H penetration into the matrix. Notably, Mg and Zr atoms spontaneously segregate to Site 1 of the Al Σ3(111)[110] GB; however, their effects are different: Mg weakens GB cohesion through charge depletion, whereas Zr significantly strengthens GBs by inducing high charge density, strong electronic localization, and d-p orbital hybridization. In addition, Zr segregation not only traps H atoms with a minimum trapping energy of -0.459 eV but also effectively suppresses H-induced damage to adjacent Al-Al metallic bonds, preserving GB strength. By contrast, Zn segregation has limited strengthening effects on GBs and may even facilitate H trapping. This study clarifies, at the atomic scale, that Zr enhances HE resistance through dual mechanisms: reinforcing GB cohesion and inhibiting H-induced degradation.

6XXX age-strengthened aluminum alloys are extensively utilized across various fields, including construction, engineering machinery, and transportation, owing to their low density, good electrical conductivity and heat resistance, and excellent overall mechanical properties. Despite such widespread applications, there are no systematic computational frameworks for these alloys that are applicable across diverse processes, including microstructure simulations and performance predictions. Notably, to facilitate the material design and industrial production of 6XXX aged-strengthened aluminum alloys, the following steps are essential: analyzing the precipitation kinetics governing the mechanical properties of 6XXX aged-strengthened aluminum alloys, developing precipitation kinetics models, establishing corresponding strengthening models correlating microstructural features with key mechanical performance metrics, and performing mechanical simulations under standard service conditions to obtain stress-strain response characteristics. Accordingly, this study introduces a full-sequence computational model for 6XXX age-strengthened alloys based on the crystal plasticity theory. The proposed model is applicable to the investigation of several characteristics, including microstructure evolution, mechanical responses, and plastic deformations. Employing “structure-property” relationships as the entry points, the mechanical behaviors of 6XXX age-strengthened aluminum alloys are described through geometrical modeling and intrinsic relationship derivations. During this process, major factors influencing mechanical properties, including grain size and morphology, precipitation data and solid solution phases, and the characteristics of non-precipitation zones at the grain boundaries, are considered. The primary task involves computationally simulating the evolution of the size distribution and volume fraction of precipitated phases as well as variations in solid solution phase contents by sizing precipitated phases according to the grain size using the Kampmann-Wagner Numerical (KWN) method. According to the dislocation-density-based strengthening of materials, an age-strengthening model and a work-hardening model are established based on the interaction mechanism between precipitated phases and dislocations. The model tracks the evolution of yield strength and work-hardening properties with aging time. A method for computing the strength contribution from the precipitation-free zone at the grain boundary and a geometrical modeling strategy are proposed. The hardening model for 6XXX is selected based on the crystal plasticity finite element method, while uniaxial tensile plastic deformation is simulated to obtain stress-strain curves. The proposed multiscale analysis model of 6XXX age-strengthened aluminum alloys constructed based on the relationships among the alloy composition, aging process, microstructures, and mechanical properties of metallic materials provides a systematic framework for designing high-performance 6XXX age-strengthened alloys. It also highlights the key role played by computational mechanics in the development of new high-strength and high-toughness aluminum alloys, offering valuable insights. Furthermore, the analytical workflow of the study is extended to the crystal properties calculation package, which is universally applicable to studies on diverse age-strengthened materials, introducing its features and functions.