Search Results (26,666)

The effect of rotary swaging (RS) at room temperature and subsequent annealing at 350 °C on the microstructure, mechanical properties, and fatigue strength of Cu–35.8%Zn two-phase brass was studied. A structure with grains of α and β′ phases elongated along the deformation direction was formed after RS. It was also shown that subgrains of 200–300 nm in size, shear bands 100–200 nm wide, and deformation twins 10–30 nm wide were formed inside the α-phase grains. RS caused the increase in the yield stress (YS) from 93 ± 4 to 717 ± 6 MPa and the ultimate tensile strength (UTS) from 332 ± 2 to 744 ± 19 MPa with a decrease in ductility (El) from 71.0 ± 2.0 to 10.3 ± 1.7%. The fatigue limit also increased from 240 to 415 MPa after RS. Subsequent annealing at 350 °C induced recrystallization of the α-phase with the formation of equiaxed grains 2.2–3.6 µm in size, which resulted in a decrease in UTS to 462–466 MPa and an increase in ductility to 44–45%. Extending the annealing time to 4 h did not affect the strength and ductility values of the alloy. Full article

Establishing an explicit correlation between dynamic machining instabilities and the terminal functional performance of difficult-to-cut materials remains challenging. Herein, a wireless sensory BT50 toolholder was deployed to in situ monitor the dynamic cutting signatures during the milling process of commercial Inconel 718 superalloy. Real-time spectral analyses captured the intensified thermo-mechanical coupling and dynamic load escalations (e.g., axial force increased from 0.56 kN to 0.65 kN) induced by progressive tool wear and anomalous grain coarsening (average grain size expanding from 45.45 μm to 56.18 μm), driven by a thermal-dominant regime at advanced wear stages and accompanied by pronounced lattice rotations and a sustained predominance of high-angle grain boundaries (HAGBs). This microstructural evolution critically governed the macroscopic corrosion degradation. The diminished grain boundary density hindered the rapid diffusion channels essential for robust passivation kinetics, whereas the highly energetic HAGB networks and reoriented crystallographic planes triggered intense localized micro-galvanic dissolution. The results formulate a comprehensive sensing-microstructure-performance closed-loop framework, offering profound mechanistic insights into the functional deterioration of critical machined components. Full article

Aluminum alloys used in aircraft structures are susceptible to corrosion fatigue cracking under combined aggressive environments and cyclic loading, threatening structural integrity. Pure data-driven models often fail under distribution shifts, while single-physics-informed neural networks (PINNs) lack flexibility in complex conditions. This paper proposes a dual-physics-informed neural network (DPINN) that integrates Walker and Forman crack growth models into a deep residual network. The model adaptively fuses both physical formulas via a trainable weight α and predicts material constants. A hybrid loss function with α regularization ensures physically consistent predictions. Using comprehensive corrosion fatigue data covering eight aluminum alloys, we evaluate the model on an internal test set and, more importantly, on an independent external test set simulating real-world distribution shifts. We further investigate an incremental learning scenario where the model is sequentially fine-tuned with increasing fractions of the external set. Results demonstrate that DPINN rapidly rectifies initial distribution mismatch, crossing the engineering reliability threshold (R² > 0.90) at an early incremental stage, and achieves superior performance after fine-tuning, significantly outperforming both a single Walker-PINN and gradient boosting regressors. SHAP feature importance analysis identifies ΔK and stress ratio as dominant drivers, confirming mechanistic consistency. The proposed architecture offers a data-efficient and interpretable tool for corrosion fatigue crack growth prediction in aluminum alloy structures. Full article

An aging population and a rising revision burden are increasing demand for bone-compatible load-bearing implants. Because the elastic modulus of conventional Ti-6Al-4V (~110 GPa) exceeds that of cortical bone (7–30 GPa), stress shielding can drive bone resorption and aseptic loosening. Two solution lines have emerged: low-modulus β-type alloys and porous architectures. Focusing on additive manufacturing (AM), this critical narrative review synthesizes the evidence along the axis of clinical failure modes. Materials science has lowered β-Ti’s modulus to ~40 GPa in bulk, yet clinical implants rely predominantly on porous conventional Ti-6Al-4V: the low effective modulus (single-digit GPa) comes from architecture, not alloying. These architectures range from porous fixation surfaces on solid acetabular shells to predominantly porous constructs—revision knee cones and sleeves, acetabular augments, and spinal interbody cages. In the acetabular cohorts, where clinical evidence is concentrated, short- to mid-term survivorship is favorable though heterogeneous; revisions were driven mainly by infection and instability, with aseptic loosening low. Two tools are proposed: a synthesis matrix setting laboratory claims alongside clinical evidence for each design parameter, and a 16-item minimum reporting checklist. Applied to the 12 primary series reviewed, the checklist found manufacturing and architecture-verification parameters largely unreported even where clinical outcomes are well documented. Full article

Electrochemical machining is widely recognized as a high-efficiency, low-cost and high-precision non-traditional machining technology for the manufacturing of turbine blade components. Nevertheless, in the practical electrochemical machining of turbine blades, the uneven spatial distribution of electric field intensity within the inter-electrode machining gap inevitably causes inconsistent anodic dissolution, which significantly deteriorates the final surface quality of machined blades. A set of comparative machining experiments were conducted on Inconel 625 superalloy. The experimental results fully verified that pulsed current machining could effectively improve the surface integrity and surface quality, and the optimal matching electrical parameters were successfully determined through systematic data analysis. The essential improvement mechanism lied in the effective suppression of stray current-induced scattered dissolution under pulsed power supply, which was highly consistent with the numerical simulation conclusions. Full article

The creep-rupture behavior and microstructural evolution of Ni–Fe-based alloy/Inconel 617 dissimilar welded joints were investigated by creep-rupture testing, interrupted creep testing, and microstructural characterization. Tests were conducted at 630–750 °C under stresses of 130–375 MPa. All joint specimens fractured in the heat-affected zone (HAZ) or base metal (BM) on the Ni–Fe-based alloy side, indicating that the Ni–Fe-based alloy side was the creep-critical region of the joint. Three failure regimes were identified according to the relative rupture lives of the joints and the Ni–Fe-based alloy BM. Fractographic observations revealed predominantly intergranular fracture, with creep cavities and cracks preferentially associated with grain-boundary discontinuous precipitation (DP) regions containing coarsened rod-like γ′ precipitates and precipitate-free zones (PFZs). Differences in DP evolution between the HAZ and BM were closely related to creep-damage localization and failure behavior. Interrupted creep tests showed that temperature was the dominant factor affecting DP formation and growth, while applied stress accelerated its evolution. DP developed rapidly during the initial exposure stage and subsequently grew more slowly. These findings clarify the relationship between grain-boundary DP evolution and creep-rupture failure in Ni–Fe-based alloy/Inconel 617 welded joints, and also provide microstructural guidance for assessing and mitigating creep degradation in dissimilar welded components used in high-temperature A-USC systems. Future work should combine longer-term creep testing, phase-resolved microstructural characterization, and predictive modeling to establish quantitative relationships among DP evolution, creep-damage accumulation, and rupture life. Full article

Centrifugally cast 35Cr45NiNb alloy has been widely employed in ethylene-cracking furnace tubes owing to its excellent carburization and creep resistance. However, the influence of microstructural degradation and temperature on its high-temperature tensile behavior remains poorly investigated. In this study, an accelerated aging method at 1200 °C for 230 h (A1) and 430 h (A2) was employed to simulate approximately 4 and 8 years of service at 1050 °C, based on the Larson-Miller parameter. The equivalence was validated by the nearly identical precipitate area fractions of the A1 specimen (16.6%) and an ex-service specimen (14.8%). Combined with SEM and EBSD characterization, tensile tests at 950, 1000, and 1050 °C were conducted to elucidate the relationship between microstructure and high-temperature tensile properties. During aging, the skeletal interdendritic M₇C₃ carbides transformed into blocky M₂₃C₆, NbC evolved into the brittle G-phase (Ni₁₆Nb₆Si₇), fine secondary M₂₃C₆ precipitates formed, and the initially continuous primary-carbide network progressively coarsened. Yield and ultimate tensile strengths decreased monotonically with increasing temperature, whereas aging produced pronounced hardening at the expense of ductility, as secondary-carbide precipitation strengthening outweighed the weakening of the primary carbide network. The fracture mode transitioned from mixed quasi-cleavage fracture at 950 °C, initiated by stress concentration at coarse phase interfaces, to ductile rupture at 1000 and 1050 °C. GND analysis further revealed an aging-dependent transition in the dominant deformation mechanism, from dislocation pile-up at the carbide network, to recrystallization after prolonged aging. Full article

In this study, an Al–20 wt.% Mg alloy was synthesized to systematically correlate its electrochemical behavior in synthetic seawater with the microstructural evolution induced by heat treatment at 190, 300, and 350 °C for 6 h. The samples characterized by SEM and XRD reveal a progressive morphological evolution of the β–Al₃Mg₂ intermetallic phase. The open circuit potential, the potentiodynamic polarization and the electrochemical impedance spectroscopy showed that this microstructural evolution increased the microgalvanic corrosion, promoting passive-film breakdown, and reducing charge-transfer resistance. The Al–20 wt.% Mg alloy treated at 350 °C exhibited the highest corrosion current density, associated with β–Al₃Mg₂. These results demonstrated that controlling beta-phase precipitation through heat treatment provides an effective approach to tune the electrochemical behavior of high-magnesium aluminum alloys. Full article

Metal-cutting operations can generate resource losses not only through the kerf itself but also through subsequent reworking, removal of altered edge material, and processing of workpieces that later prove unsuitable. This study develops and experimentally evaluates an automated eddy-current inspection system intended to characterize metal edges immediately after cutting. The system combines a miniature high-frequency eddy-current transducer, three-axis positioning, digital signal acquisition, and software-based processing. A clad D16AT aluminum alloy specimen with edges produced by laser cutting, cold sawing, and hot shearing was scanned. The air-to-metal transition profiles were described by a logistic function, yielding an electromagnetic transition coordinate xc, a transition parameter s, and the coefficient of determination R². The fitted xc values were 7.30, 8.76, and 8.93 mm for cold-sawn, laser-cut, and hot-sheared edges, respectively; s was 0.64, 0.59, and 0.67 mm, while R² was 0.961, 0.959, and 0.941. These quantities are interpreted as comparative electromagnetic descriptors and not as direct measurements of heat-affected-zone depth or defect probability. A scenario calculation based on the displacement of the electromagnetic transition relative to the geometric edge gave apparent material-removal indices of 0.192, 1.127, and 1.236 g per 40-mm edge. Under this explicitly model-based scenario, the laser-cut edge was 8.8% lower than the hot-sheared edge. Complementary measurements showed concordant ordering of the electromagnetic descriptors with roughness, burr height, HV0.1, altered-zone depth, conductivity, and removed-layer mass; the apparent and measured masses differed by 0.3–1.1% for this specimen. The results demonstrate that automated eddy-current mapping can differentiate edge states and provide structured data for routing decisions in resource-efficient and zero-defect manufacturing. Independent-specimen replication, fully traceable physical characterization, and production-scale validation are required before the descriptors can be used as acceptance thresholds or as direct estimates of actual waste. Full article

This study investigated the combined influence of the α/β phase proportion and Plasma Electrolytic Oxidation (PEO) on the wear behavior of Ti-6Al-4V alloy. Samples with distinct α/β phase ratios induced by previous heat treatments (600, 800, and 1000 °C) were subjected to dry sliding wear tests before and after PEO treatment. The untreated samples exhibited major abrasive and minor adhesive wear mechanisms, characterized by broad scratches and minor adhered debris. In contrast, PEO-treated samples exhibited predominant adhesive wear, indicating a significant tuning in the wear mechanism. The coefficient of friction (COF) was unaffected by phase proportions in untreated samples but was influenced by PEO treatment. Volume loss and wear rate were sensitive to phase composition, with the untreated samples heat-treated above 800 °C exhibiting the highest values, likely due to the retention of the metastable α′ phase. Conversely, PEO-treated samples demonstrated markedly reduced wear, confirming the protective role of the oxide layer. Energy-dispersive spectroscopy (EDS) revealed the counterbody’s particle adhesion in untreated tracks, whereas PEO-treated tracks retained the coating, evidencing superior wear resistance. These findings highlight that tailoring the α/β ratio through heat treatment combined with PEO treatment enhances wear performance, offering promising implications for clinical translation in biomedical implants. Full article

Ultrasonic vibration-assisted machining (UVAM) can improve the machinability of difficult-to-machine titanium alloys; however, the relationship between machining-load fluctuations, subsurface microstructure, and electrochemical response remains insufficiently established. In this study, a wireless in-situ monitoring system was integrated with electron backscatter diffraction (EBSD), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and scanning electrochemical microscopy (SECM) to compare conventional milling (CM), low-excitation UVAM (L-UVAM), and high-excitation UVAM (H-UVAM) of Ti-6Al-4V. Under the investigated conditions, H-UVAM reduced the RMS value of the measured axial load signal by 43.3% compared with CM and decreased the variation in the resultant bending-moment signal. The EBSD results showed a reduction in the mean grain size from 11.67 μm for CM to 10.07 μm for H-UVAM, together with an increase in the measured high-angle grain-boundary fraction from 48.27% to 59.39%. Electrochemical measurements further indicated a lower corrosion current density and a higher fitted barrier resistance for the H-UVAM surface. SECM mapping showed a narrower local current distribution under H-UVAM than under CM. These results demonstrate a consistent association between reduced machining-load fluctuations, modified subsurface crystallographic features, and improved electrochemical response. Because surface roughness, residual stress, tool wear, and passive-film chemistry were not independently quantified, the present work does not attribute the corrosion response exclusively to microstructural changes. Instead, it provides a cross-scale experimental framework for correlating machining dynamics with surface integrity and corrosion-related performance in machined titanium alloys. Full article

PGM (platinum-group mineral) melt inclusions set in two Pt-Fe alloy nuggets are from the Camumbi River placer, Ecuador. Inclusion bulk compositions are strongly fractionated, mutually exsolved melts Pt–Rh–Pd–Cu > Fe–Ni sulfide-rich and Pt–Cu–Rh ≈ Pd > Fe–Ni telluride-rich respectively, with metal/ligand ratios ~1. They are related to a higher T melt inclusion bulk composition Fe–Cu–Pt >>> Pd > Rh–S also a monosulfide. We use increasing Me/S,Te mineral ratios of inclusion PGM to define each inclusion PGM paragenesis. In the S-rich inclusion, skeletal cuprorhodsite crystallized first with co-exsolved Pt-Fe alloy upon cooling. Next crystallized are braggite, vysotskite, Pt-Fe alloy and oosterboschite. Last crystallized minerals are phase (Pd,Pt)₃(S,Se,Te)₂ and keithconnite (similar synthetic phases are stable at ~350 °C). Within the Te-rich S-bearing inclusion, cooperite first crystallized at high T (~1100 °C) from a subordinate, exsolved S-rich melt. The co-exsolved Te-rich melt next crystallized rare interstitial PGM Rh-bearing mitrofanovite, Rh-bearing moncheite, Rh-bearing monchetundraite, hongshiite, and six minor PGM. Experimental mitrofanovite and moncheite are stable at high T while monchetundraite is stable ~350 °C. We suggest that Rh-bearing mitrofanovite and Rh-bearing monchetundraite could form separate solid solution series with variable Pt–Rh and Ni–Rh respectively. Rh-bearing moncheite indicates a solid solution series with end-member UM (unnamed mineral) Rh(Te,Bi)₂ reported from Ethiopia. Six minor PGMs with extreme compositions are identified by phase mapping using pixel counts combined with BSE (backscattered electron) images. They are stable at lower T hydrothermal conditions and compare with pyrrhotite and pentlandite breakdown products of high T experimental MSS (monosufide solid solution). We suggest the inclusions represent decompression melts formed in the apices of ascending unknown Alaskan–Uralian-type intrusion(s)/volcanics within the Cretaceous Naranjal accreted arc terrane. The melt inclusions are late-formed in the long-fractionating history of this previously defined ore system, and lack detectable As, Sb and Bi suggesting exsolution of higher temperature melts. Full article

Water-jet guided laser (WJGL) technology has gained significant attention in precision manufacturing due to its extremely small heat-affected zone. However, laser-induced water breakdown severely constrains the achievable laser power and processing efficiency. This paper presents and validates an optical solution employing a custom-designed rotationally symmetric aspheric lens. The lens is designed to generate a sequence of discrete focal points distributed along the optical axis. This configuration maintains a high average laser power while suppressing the peak power density at each individual focus below the water breakdown threshold. Theoretical modeling and ray tracing simulations confirm the superior performance of the lens in creating a controllable multi-focal beam. Experimental results demonstrate that a WJGL system incorporating the six-focus aspheric lens operates stably at 350 W. This represents a 300 W increase compared to the conventional spherical lens, which had a stable operating power limit of approximately 50 W within this experimental system. In microgroove machining experiments on NiTi alloy, the new system achieved an approximately 3.5-fold increase in groove depth and a 2.7-fold reduction in taper angle. This study provides a practical and effective beam shaping strategy to overcome the fundamental power limitation in WJGL technology. Full article

Among the ferromagnetic shape memory alloys (SMAs), Ni43Mn31Ga19Co7 (at%) alloys are well known as a promising ferromagnetic SMA (FeSMA) for magnetocaloric effect, and scientific interest has increased due to the possible exploitation of multicaloric function. This first example of multi-effect by coupling elastocaloric and magnetocaloric effect is still far from complete experimental validation, mainly due to the difficulty of testing conditions that require the simultaneous application of both fields. In this study, a low magnetic field (μ₀H = 0.26 T and 0.56 T) is applied during elastocaloric deformation at different temperatures. Although the magnetic field values applied in this work are much lower than those usually considered in the magnetocaloric effect, the magnetic field improves the elastocaloric effect, increasing the total strain and reducing the critical stress and mechanical hysteresis. This synergic action allows us to obtain an increase in the ΔT_ad of about 13% and 25% upon loading and unloading, respectively. Full article

The coarse Fe-containing intermetallics (IMCs) induced by excessive Fe levels seriously degrade the mechanical and corrosion properties of recycled aluminum alloys. Controlling the nucleation and growth behavior has been confirmed as effective in refining the Fe-containing intermetallics (IMCs) and enhancing the ductility of recycled aluminum alloys. In this work, the modification mechanism of Al–Ti–B in Al–2Fe alloy was systematically investigated by combining SEM microstructure, TEM characterization and DFT calculations. TEM observations reveal that TiB₂ particles are preferentially embedded within Al₁₃Fe₄ phases, forming coherent or semi-coherent interfaces, which act as nucleation sites and facilitate the refinement and uniform distribution of Fe-containing IMCs. Interface property calculation results show that the Al₁₃Fe₄ (620)/TiB₂ (01$\stackrel{\mathrm{-}}{1}$1) interface exhibits lower lattice mismatch (4.4%) and interface energy, indicating stronger interfacial bonding and higher interface stability. The electronic structure results showed that the enhanced interface stability is attribute to the pronounced charge redistribution. Stable interface structure reduces the heterogeneous nucleation barrier and promotes refinement efficiency of Fe-containing ICMs. This study provides theoretical guidance for the refinement of Fe-containing impurity phases and high-performance sustainable recycling of aluminum alloy scrap. Full article