This study employed a gradient heat treatment strategy to efficiently acquire microstructure parameters and establish the microstructure-hardness relationship in Ti-6Al-4V-1.5Zr-1.0Nb-0.5Mo alloy, addressing the knowledge gap in rapid optimization of heat treatment windows. Gradient solution treatment in the α + β region (859-928 °C) revealed that hardness reaches a minimum at a Vαp/Vβt ratio of approximately 0.5, a condition to be avoided if aging is not applied. Subsequent aging at 500 °C, a common temperature for such alloys, highlighted the solution-treated sample at 908 °C as possessing high hardening potential, attributed to its high βt fraction (Vβt = 70%) and sufficient retained β phase that promoted fine αs precipitation. Gradient aging (502-590 °C) of this optimized microstructure further showed that peak hardness (>350 HV1, measured under a 1 kg load) was achieved at 502 °C and 551 °C, where the Vαp/Vβt ratio remained near the optimal 3:7, and the precipitated refined αs exhibited minimal width. The hardness of the bimodal microstructure is governed by two principal factors: the Vαp/Vβt ratio (optimum near 3:7) and the precipitation efficiency of refined αs from retained β phase. The gradient approach proves to be an effective high-throughput method for rapidly correlating heat treatment parameters with microstructure and properties, accelerating the design of heat treatments for titanium alloys.

The effects of microalloying of Sc and Hf on the microstructure and intergranular corrosion (IGC) behavior of a cross-alloyed Al-Cu-Zn-Mg alloy were investigated. Results indicate that the addition of Sc and Hf significantly refines grain size in both as-cast and hot-rolled alloys, altering grain structure and multiscale precipitates characteristics. It was revealed that the corrosion behavior of the alloy transformed from severe intragranular corrosion into IGC after the addition of Sc. In contrast, the Hf-microalloyed alloy exhibited predominantly pitting with excellent IGC resistance. This was attributed to the segregation of Hf atoms at grain boundaries (GBs) suppressed the continuous precipitation of eta and S phases, narrowing the precipitation-free zone (PFZ). The discontinuous distribution of grain boundary precipitates (GBPs) and the narrowed PFZ inhibited the anodic dissolution, thereby reducing IGC sensitivity. Interestingly, the Hf-containing alloy exhibit smaller grain sizes, a higher proportion of low-angle grain boundaries (LAGBs) and coincident site lattices (CSL), which synergistically contribute to the enhanced IGC resistance.

The lightweight high-entropy alloys of Al49Ti21V7Cr18Six (x = 0, 1, 2, 3) were synthesized by vacuum arc melting, with density of only 4.04-4.13g·cm-3. The dependence of microstructural evolution, mechanical properties, and passivation behavior on Si content was systematically examined. Meanwhile, the regulation mechanism of the defect structure within the passive film was also clarified. The addition of Si induced the precipitation of the Ti5Si3 phase and altered elemental partitioning behavior. The Al49Ti21V7Cr18Si1 alloy achieved the maximum compressive yield strength of 2097MPa, while further Si addition resulted in progressive reductions in both strength and ductility. Furthermore, with increasing Si content, the corrosion behavior gradually transformed from active dissolution to stable passivation, while the corrosion current density decreased significantly. In addition, within the point defect model (PDM) framework, high-valence Si ions may inhibit the formation of oxygen-vacancy-related donor defects via a charge-compensation mechanism. Effective donor and acceptor densities were reduced, while defect-mediated Cl⁻ transport was hindered. Moreover, oxidized Si and Cr3+-containing species were detected within the passive film, while increased Al2O3 contribution was also observed. Such chemical-state changes were associated with the transformation of the passive film from loose hydrated structure to denser oxide state. Ultimately, Cr- and V-enriched interdendritic regions and Ti- and Si-rich interfaces may promote pitting initiation, whereas Si-containing passive films suppress pit propagation. Overall, Si content regulates the coupled evolution of mechanical properties and passivation behavior in this alloy system.

In addressing the unclear decoupling and synergistic mechanisms of thermal and non-thermal effects in the electrical-assisted forming of Ti-6Al-4V (TC4) titanium alloy, this study quantitatively analyzes the mechanical contribution of non-thermal effects by combining pulsed current-assisted tensile testing, isothermal tensile testing, and thermoelectric coupling numerical simulations. The microstructural evolution is further revealed through electron backscatter diffraction (EBSD) and Transmission Electron Microscope (TEM) characterization. The results indicate that the proportion of non-thermal effects varies non-monotonically with increasing current density, reaching a peak of 21.89% at 6.93 A/mm², which leads to a reduction of peak stress by 127 MPa compared to isothermal tensile testing. At the microstructural level, EBSD analysis shows that non-thermal effects reduce the average misorientation of the nuclei, promote dislocation migration towards grain boundaries, and accelerate dynamic recrystallization nucleation. Additionally, it facilitates the transformation of the deformation mechanism from basal slip-dominated to multi-slip system cooperation. TEM characterization further reveals that the non-basal slip of dislocations is enhanced. Pulsed current effectively promotes the non-basal slip and proliferation of dislocations while suppressing the formation of Frank dislocation rings and basal stacking faults, which hinder dislocation motion during high-temperature deformation. Pulsed current also significantly facilitates the precipitation of the β phase by lowering the free energy barrier for the α→β phase transformation, even under conditions below the traditional transformation temperature. As the current density increases, the material’s deformation mechanism transitions from dislocation accumulation-dominated to a synergy of dislocation slip, dynamic recrystallization, and phase transformation.

The phase transformation-induced plasticity (TRIP) effect is a potent mechanism that simultaneously enhances the strength and ductility of materials. In this study, L12 precipitates were introduced into low stacking fault energy (SFE) FCC-phase TRIP-type multi-principal element alloys (MPEAs) to investigate their influence on the FCC→HCP deformation-induced phase transformation through uniaxial tensile testing at room temperature. The L12 precipitates significantly enhance the strength of the alloy. Their presence inhibits the formation and propagation of stacking faults (SFs), thereby suppressing the FCC→HCP transformation. This phenomenon arises from the combined effect of two factors. Firstly, the dispersed distribution of L12 precipitates generates high-SFE zones that segment the FCC matrix and reduce the dislocation channel width. This increases the critical stress required for the formation of the first SF loop, thereby inhibiting SFs formation, thus preventing the subsequent generation of the HCP phase. Secondly, the higher SFE of the L12 precipitates relative to the matrix causes propagating SFs to be effectively pinned, thereby restricting their motion. The present work elucidates how coherent L12 precipitates suppress the transformation process, providing a mechanistic basis for tailoring metastability in TRIP-type MPEAs through nanoscale precipitation engineering beyond conventional compositional design.

In this study, AlCoCrFeNi high-entropy alloy composite coatings with different WC–Ti contents were fabricated on 45 steel substrates by laser cladding. The formation mechanism of the in-situ TiC reinforcing phase, which originated from the partial decomposition of WC during laser cladding and the subsequent reaction between the released C and Ti, was systematically clarified. The strengthening mechanism associated with the coexistence of BCC and TiC/WC phases under non-equilibrium solidification conditions was revealed, and the effects on phase constitution, microstructure, mechanical properties, and corrosion resistance of the coatings were investigated. The results showed that the coatings exhibited a gradient composite structure with a BCC phase matrix, in which TiC particles were enriched in the upper region to enhance wear resistance, while the bottom region containing WC particles provided load-bearing support and grain refinement. The average grain size of the coating was refined from 42.3 μm to 2.2 μm, and the maximum microhardness increased by 33.4% to 709.7 HV0.2. With increasing WC–Ti content, the load-bearing capacity and micro-cutting resistance of the coatings were enhanced, and the wear mechanism gradually transformed from adhesive wear to abrasive wear and fatigue wear. Meanwhile, the minimum friction coefficient decreased by 15.3% to 0.459. In terms of corrosion performance, an appropriate WC–Ti addition improved the corrosion resistance of the composite coatings in 3.5 wt.% NaCl solution. The corrosion potential increased from -747.75 mV to -402.38 mV, corresponding to an increase of 46.2%, and the coatings exhibited superior passivation behavior and impedance characteristics. The optimal charge transfer resistance was 2.3 times higher than that of the coating without addition. This study provides a theoretical basis for composition design and property regulation of WC–Ti synergistically reinforced high-entropy alloy coatings.

This study reported a strategy of Sc-Hf microalloying and thermomechanical processing to synergistically regulate the layered heterogeneous grain structure and multiscale precipitates in Al-Cu-Zn-Mg alloys. The results indicated that the combined addition of Sc and Hf achieved optimal grain refinement in Al-Cu-Zn-Mg alloys (reducing grain size by 64.3%). Through thermodynamic calculations and microstructural characterization, the evolution of precipitates during solidification and the influence of Sc and Hf atoms on the competitive behavior of multi-phase co-precipitation during aging were elucidated. Following the thermomechanical processing, the coarse second phase particles in the Sc-containing alloy promoted recrystallization through particle-stimulated nucleation; meanwhile the submicron second-phase particles pinned the grain boundaries to inhibit the growth of the recrystallization grains, thereby forming a layered heterogeneous grain structure. The yield strength, ultimate tensile strength and elongation of the Sc-Hf-alloyed alloy reached 457 MPa, 558 MPa and 12.5%, respectively, representing the improvements of 16.0%, 14.6%, and 30.2% over the base alloy, respectively. Strength gains stemmed from the multiple precipitates with a higher number density and a smaller size, the reduced deformed grains and the increased dislocation density. Furthermore, the heterogeneous grain structure simultaneously retarded the crack propagation and mitigated the stress concentration near coarse/fine grain interfaces, resulting in more uniform plastic deformation and improving ductility. The present work offered a novel approach for synergistically enhancing strength and ductility in Al-Cu-Zn-Mg alloys.

The influence of Zn on the microstructure and corrosion behaviour of AZ9x magnesium alloys containing 0–3 wt.% Zn was investigated in the as-cast and solution-treated conditions. Increasing Zn additions reduced both the hydrogen-derived corrosion rate and the corrosion current density in each condition. Correlative electron microscopy and Kelvin probe force microscopy (KPFM) revealed that dissolved Zn raised the apparent work function of α-Mg more strongly than that of Mg17Al12, Al8Mn5, Al11Mn4 and φ-Mg(AlZn), thereby reducing the Volta-potential difference between α-Mg and these phases. Density functional theory (DFT) calculations reproduced this trend and showed that Zn enrichment of the α-Mg surface increased its work function substantially more than Zn enrichment of Mg17Al12. Following solution treatment, Mg17Al12 dissolved and Al8Mn5 transformed to Al11Mn4, leaving most Zn in solid solution in α-Mg which further narrowed the Volta-potential difference, but the lack of Mg17Al12 removed a barrier to corrosion propagation. Overall, zinc additions improved corrosion resistance primarily by electrochemically homogenising the microstructure and reducing local galvanic driving forces.

Secondary aluminum alloys offer substantial reductions in energy consumption and carbon emissions, but elevated iron impurities in recycled feedstocks promote the formation of Fe-bearing intermetallics that degrade mechanical performance. This article demonstrates how different concentrations of Y alloys (0, 0.15, 0.3 and 0.6 wt.

To develop high-performance WC-based cemented carbides, La₂O₃/WC composite powders were first synthesized via a co-precipitation-carbonization route, followed by high-energy ball milling with Co powders and subsequent spark plasma sintering (SPS) to fabricate La₂O₃/WC-10Co cemented carbides. The effects of the carbonization parameters and C/W molar ratio on the phase constitution, microstructure, and elemental distribution of the La₂O₃/WC composite powders were systematically investigated. The influence of La₂O₃ addition on the microstructural evolution and mechanical properties of the sintered cemented carbides was also further elucidated. The results show that ultrafine La₂O₃/WC composite powders with high phase purity and homogeneous elemental distribution can be obtained under the optimized carbonization conditions, with particle sizes ranging from 320 to 400 nm. The addition of La₂O₃ effectively suppresses WC grain growth during sintering and improves the mechanical properties of the cemented carbides. At a La₂O₃ addition of 0.6 wt.%, the La₂O₃/WC-10Co cemented carbide exhibits better mechanical properties with a Vickers hardness of 1951.31 HV30 and a fracture toughness of 15.36 MPa·m¹/², corresponding to increases of approximately 10% and 8.7% compared with the La₂O₃-free sample, respectively. These findings indicate that combining co-precipitation–carbonization with SPS is an effective approach for producing high-performance ultrafine-grained La₂O₃/WC-10Co cemented carbides.

A 2.62 g/cm3 Al-3Mg-2Cu-1Li cross-over alloy micro-alloyed with Sc/Zr/Ti was designed to break the strength-corrosion-density dilemma of 5xxx and 2xxx alloys. Following 80% hot-rolling, solution treatment, and 200 degrees C ageing, 1 wt% Li refined GPB zones to 1.8 nm, tripled their number density, and suppressed grain-boundary precipitation, enhancing precipitation hardening and increasing ultimate tensile strength by 30 MPa while maintaining-12% elongation. Although Li increased intergranular corrosion susceptibility at peak age, over-ageing to 75 h coarsened grain-boundary precipitates, disrupting anodic paths and restoring corrosion resistance comparable to Li-free alloys while retaining the strength advantage. This delivers a transferable lightweight Al-sheet platform (2.6 g/cm3,-450 MPa) with balanced formability and corrosion tolerance in the over-aged condition for weight-critical applications.

2 x x x series Al-Cu-Mg alloys with high specific strength (strength/weight ratio), good formability, corrosion and heat resistance are widely used in the aerospace industry (e.g. fuselage structures). This paper reveals the effect of 0.2 wt% Sc microalloying on the hardness, heat and corrosion resistance as well as microstructure of an Al-4.3Cu-1.6 Mg (wt%) alloy under varied heat treatment processes using high-angle annular dark-field in scanning transmission electron microscopy and differential scanning calorimetry etc. The results show that Sc minor addition contributes to the improved heat and corrosion resistance of the peak-aged Al-Cu-Mg-Sc alloy under different solution and aging treatment parameters, despite of a slight decrease in peak hardness. The improved corrosion resistance of the peak-aged Al-Cu-Mg-Sc alloy is related to the formation of discontinuous grain boundary precipitates and narrower precipitation free zones. The increased heat resistance and slightly reduced peak hardness of the Al-Cu-Mg-Sc alloy compared to Al-Cu-Mg alloy are mainly due to the increased formation temperature and decreased number density of the main strengthening S precipitates by Sc.

Optically dark areas (ODAs) on fatigue fracture surfaces of Al-Cu-Mg alloys, linked to premature failure, exhibit Cu-rich nanoparticles and surface oxidation. The mechanism driving Cu enrichment in ODAs (between mechanical friction and thermal diffusion) remains debated. To clarify, mechanical fragmentation (ball milling) and high-temperature annealing (500°C, air/nitrogen) were employed. Ball milling induced surface furrows and Al oxidation but no significant Cu segregation, indicating friction alone is insufficient. Conversely, thermal exposure promoted marked Cu diffusion and surface enrichment, with nitrogen yielding higher Cu-rich phase coverage (via XRD/DSC confirmed) and stronger light absorption (metallic Cu dominance) compared to air (CuO formation). Results demonstrate thermal diffusion, not mechanical friction, dominates Cu enrichment in ODAs. This mechanistic insight provides a pathway to enhance fatigue resistance in Al-Cu-Mg alloys by controlling Cu segregation during service.

Titanium-based materials such as Ti-6Al-4V alloy have been widely applied in the field of biomedical implant materials due to their excellent mechanical properties and fatigue resistance, while their biological toxicity and the lack of antimicrobial properties limit their service reliability and life. Developing the novel Ti-based material with excellent mechanical properties and multiple biofunctions is still an open issue. In this work, the novel Ti-Ta-Cu alloys were designed and fabricated by regulating the Cu content, and the relationship between microstructures and mechanical properties, wear resistance, corrosion resistance, in vitro biocompatibility, and antibacterial properties were investigated. It was found that the Ti-Ta-Cu alloys consist of alpha phase and the Ti2Cu precipitates, with the average grain size varying from 158 mu m to 210 mu m and severe lattice distortion. In addition, the Ti-Ta-Cu alloy with 0.75 wt% Cu has the best comprehensive compression mechanical properties, its yield strength, compressive strain, and Young's modulus is 1178.8 +/- 13.2 MPa, 26.4 +/- 0.7 %, and 112.89 +/- 3.70 GPa, respectively. The high strength dominantly comes from the solid solution strengthening and the good ductility derives from the refined grain size. Moreover, in comparison to Ti-6Al-4V alloy, the fabricated Ti-Ta-Cu alloys have worse wear resistance but much better corrosion resistance in SBF solution, biocompatibility, and antibacterial properties. This study sets insight for synthesizing Ti alloys with excellent mechanical properties and multiple biofunctions for the biomedical implanting application.

Elastocaloric effect of NiTi alloys is highly sensitive to Ni concentration due to the change in microstructure and phase transformation characteristics. To illustrate the effect of a wide composition range on microstructure evolution and elastocaloric capacity of NiTi alloys, a series of in-situ metallurgical NiTi alloys with Ni concentration from 45.8 at% to 56.7 at% were fabricated by laser additive manufacturing (LAM) technology. Results indicated that grain morphologies of LAM NiTi specimens with an increase of Ni concentration changed from cellular-like to columnar-like and finally transfer to equiaxed-like, corresponding to peritectic, isomorphous and hypoeutectic solidification behaviors. Significant composition changes from Ti-rich to Ni-rich in LAM NiTi alloys strongly affected phase transformation temperature and latent heat of transformation from martensite to austenite (Delta H-M -> A), resulting into different elastocaloric testing conditions. For Ti-rich LAM NiTi specimens with 45.8-49.4 at% Ni, a higher Ni concentration corresponded to a less amount of blocky Ti2Ni particles and a higher latent heat (similar to 24 J/g for 49.4 at%), while austenite finish temperature (A(f)) of the alloys with different compositions was similar (similar to 100 degrees C), suggesting a high elastocaloric testing temperature requirement. For Ni-rich LAM NiTi specimens with 52.3-56.7 at% Ni, microstructures showed an apparent difference compared to Ti-rich LAM NiTi specimens, in which both plate-like Ni3Ti phase and nano-size needle-like Ni4Ti3 particles precipitated from B2 phase matrix. With increase of Ni composition, the size and amount of Ni3Ti particles increased, while Ni4Ti3 particles decreased. All of the Ni-rich LAM NiTi alloy specimens exhibited low dHM -> A and low Af value of similar to 10 degrees C, but showed strong elastocaloric cooling capacity in a room-temperature superelastic condition. With an increase of Ni concentration, the maximum recoverable strain of Ni-rich LAM NiTi alloy specimen decreased, and cooling adiabatic temperature change (Delta T-c) of which at the same strain initially increased and then decreased due to B2 phase amount change. Furthermore, LAM Ni52.3Ti47.7 alloy specimen with the maximum recoverable strain of 2.4 % had a dTcvalue of -8.2 degrees C; in contrast, a maximum Delta T-c of-15.4 degrees C was achieved in LAM Ni54.5Ti45.5 alloy specimens at 4 % strain. These results revealed that in-situ metallurgy LAM technology can be one potential technology for fabricating composition-tuned NiTi alloy with large elastocaloric cooling capacity.

Assisted by CaO powder, the regenerated cathodes are successfully achieved through the removal of CaF 2 and deliver a considerable capacity and excellent rate performance.

The interfacial properties of metal composites, governed by diffusion and intermetallic compound (IMC) layers, critically influence their mechanical property. This study systematically investigates the evolution of these layers at the interface of explosion-welded TA1/Q235 clad plates during hot rolling, aiming to clarify their effects on mechanical properties. Multi-pass hot rolling at 700 degrees C regulates IMC formation and fragmentation, with grain size increasing and dislocation density peaking at 70 % deformation before declining. The diffusion layer thickens initially, transforms into IMC, and fragments with increasing deformation. Correspondingly, tensile strength (496 MPa) and shear strength (395 MPa) peak at 50 % deformation - reflecting increases of 55 % and 18 %, respectively - before decreasing. This work establishes a novel framework for optimizing interfacial stability and mechanical property in Ti/steel composite plates, offering insights applicable to diverse dissimilar metal systems.

To address the persistent challenge of balancing room and elevated temperature mechanical properties in conventional near alpha titanium alloys, this study proposes an innovative approach through compositional design and thermomechanical treatment process optimization. A high Zr/Si containing near-alpha titanium alloy is developed by decreasing-temperature multidirectional forging (DMDF) and subsequent heat treatment, yielding a trimodal microstructure consisting of lamellar primary alpha-phase (alpha(l)), equiaxed primary alpha-phase (alpha(e)) and transformed beta-phase (beta(t)). This microstructure features a hierarchical dispersion of dual-scale silicides, where submicron-scale silicides are preferentially distributed along grain/phase boundaries, while nanoscale silicides are uniformly dispersed within grains. After DMDF followed by solution treatment at 950 degrees C/40min (HT2), the alloy achieves superior room-temperature mechanical properties (UTS = 1306.6 MPa, EL = 7.5 %), primarily attributed to synergistic strengthening effects involving multiscale precipitates (alpha(S) and dual-scale silicides), dislocation networks and activated slip systems. The alloy maintains excellent strength at elevated temperature up to 650 degrees C, demonstrating a UTS of 799.8 MPa paired with an elongation of 16.2 %. This sustained strength originates from strain gradient formation at alpha/beta interfaces combined with dual-scale silicides pinning mechanisms. Additionally, the enhanced ductility at 650 degrees C arises from the slip bands within the alpha-phase and additional dislocation activation. This design strategy of trimodal microstructure with hierarchical dispersion of dual-scale silicides provides a new perspective for tailoring high-temperature titanium alloys with balanced mechanical properties at both room and elevated temperatures.

In this study, the effect of vanadium (V) addition on the microstructure and heat resistance of 2519 alloy was investigated by phase diagram calculations and experiments. The addition of V leads to the formation of the primary Al10V phase, which exists in two forms: octahedral and hexagonal disk morphologies particles. TEM results show that a spherical, coherent Al18Mg3V2 phase precipitates in the alloy after aging treatment. Heterogeneous nucleation of the θ′ phase on Al18Mg3V2 phase was observed. For the first time, the orientation relationship between the Al18Mg3V2 phase and the aluminum matrix was determined. The Al18Mg3V2 phase demonstrated excellent thermal stability during thermal exposure, with its average size remaining at 57 nm after 1000 h at 250 °C. The experimental results show that 0.3 V alloy exhibits the highest strength at 350 °C, 33