The loading ratio (explosive mass to flyer plate mass) plays a critical role in explosive welding for achieving effective metallurgical bonding. The understanding of the bonding mechanism in explosive welding is challenging due to the simultaneous occurrence of multiple complex phenomena, including detonation, severe plastic deformation induced by high-velocity impact, extremely high pressures, and rapid temperature rise within microseconds. Therefore, this study employs Smoothed Particle Hydrodynamics (SPH) available in the Ansys Autodyn to numerically analyze dissimilar explosive welding (AZ31B and Al 5052) at different loading ratios (R = 0.7–0.9). The numerical analysis provides critical insights towards the bonding mechanism. At a higher loading ratio (0.9), an undulating interface with greater amplitude is observed due to intense plastic deformation. Interfacial pressure increases with loading ratio, reaching values approximately 18
To investigate the effects of extrusion temperature and Ca, Al additions on the microstructure and corrosion resistance of Mg-Sr-based alloys, Mg-2.5Sr(wt
Wire arc additive manufacturing (WAAM) represents a modern fabrication process capable of producing medium to large-scale components efficiently and at a relatively low cost, owing to its high deposition rate. In this work, the influence of different wire feed rates on the first-layer deposition using the WAAM–GMAW (gas metal arc welding) process of Al-5356 alloy was examined, while keeping the torch angle and travel speed constant. Results indicate that changes in wire feed rate substantially influence the bead geometry, microstructure, mechanical characteristics, residual stresses, and texture formation of the deposited layer. The maximum bead height was achieved at a wire feed rate of 7 m/min, whereas the maximum bead width occurred at 6 m/min. Moreover, residual stress increased progressively as the feed rate rose from 6 to 8 m/min. Additionally, deposition at 7 m/min exhibited prominent texture characteristics, while the highest microhardness was recorded at 8 m/min compared to 6 m/min and 7 m/min. These results emphasize the crucial role of wire feed rate in optimizing the properties of WAAM-deposited Al-5356 alloy. The study provides valuable insights for refining additive manufacturing processes to achieve desired material characteristics for specific applications.
This study systematically investigates the influence of TiO2 crystallographic phases—amorphous, anatase, and rutile—on the tribological performance and suspension stability of SAE 10W40 engine oil. TiO2 nanoparticles were synthesized via a sol–gel method and calcined at 100 °C, 450 °C, and 900 °C to obtain pure amorphous, anatase, and rutile phases, respectively. Characterization by XRD and FESEM confirmed that higher calcination temperatures led to phase transformation and significant grain growth, from 13 nm (anatase) to 58 nm (rutile). Tribological tests using a pin-on-disk tribometer revealed that dispersing 0.2 wt.
The processing of increasingly complex sulphide ores with difficult mineralogical compositions requires a careful selection of flotation reagents, their optimal preparation and rational combination of various collectors. This work investigates the colloid–chemical properties of reagent systems based on a sulphur-containing product as well as its mixtures with aeroflot and sodium butyl xanthate in various ratios. Measurements of the contact angle and zeta potential were taken on monomineral copper, lead, zinc and iron. At a ratio of [sulphur-containing product (SP)]:[sodium butyl xanthate (BX)]:[sodium butyl dithiophosphate (BTP)] = 1:1:1, the maximum hydrophobicity values were recorded: 96.79° for chalcopyrite, 99.22° for galena, 78.23° for pyrite and 60.03° for sphalerite. Flotation tests showed that the use of a sulphur-containing collector based on [refined oil (RO)]:[sulphur-containing product (SP)]:[sodium butyl xanthate (BX)] = 0.8:0.2:1 at a consumption rate of 120 g/t in combination with BTP (120 g/t) in a closed cycle increases the extraction of copper in the rough collective concentrate by 15.25
The effect of Si₃N₄ loading on the resulting microstructure, mechanical hardness, and anti-corrosion performance was systematically evaluated by electrodepositing Ni–W–Si₃N₄ alloy layers under the direct influence of a current. With rising Si₃N₄ concentration, the deposit surface became progressively smoother, and the maximum coating thickness (16.92 μm) was recorded at 1.5 g/L. Microhardness exhibited a bell-shaped response to particle addition, peaking at 457 HV at the same concentration. The coating deposited at 4 g/L exhibited the minimum self-corrosion current density (7.45×10⁻5 μA cm⁻2) and the maximum charge-transfer resistance (2941 Ω cm2). This enhanced corrosion protection is primarily attributed to the synergistic interplay of grain refinement, strong (111) crystallographic texture, and improved surface quality.
It is important to understand the effect of volatile matter in coal on reduction, which could be used for the reduction of metal oxides. A new pyrolysis model of coal was put forth, and the model parameters were estimated using TG data and genetic algorithm. According to the model calculations, the maximum pyrolysis temperature and the amount of volatile matter released in the high temperature region increased with the increase in heating rate. Pyrolysis of the coal used in the experiment was completed within 5 min above 1400 °C. According to the model calculations under real heating conditions, Pyrolysis rate reached a maximum at 717 °C. Volatile matter released in the temperature regions of 700–1100 °C and 1100 °C are 50
Ti–5Cu alloy was fabricated by electron beam cold hearth melting and multi-pass rolling. The effects of aging treatment on microstructural evolution, precipitation behavior, and mechanical properties were investigated by XRD, SEM, TEM, and room-temperature tensile testing. The results show that α′-Ti gradually transformed into stable α-Ti during aging, while β-Ti transformed into uniformly dispersed spherical Ti₂Cu precipitates. Aging treatment significantly improved the mechanical properties of the alloy. With increasing aging temperature and prolonged aging time, Ti₂Cu precipitates gradually nucleated and coarsened, and the microstructure evolved from a typical Widmanstätten structure toward a basketweave structure. The alloy exhibited a nonlinear mechanical response, with strength first increasing and then decreasing, while ductility initially decreased and subsequently recovered. Among all conditions, the 440 °C/12 h + 480 °C/12 h T6-treated sample exhibited the best comprehensive properties, with an ultimate tensile strength of 991 ± 5 MPa, yield strength of 902 ± 3 MPa, elongation of 10.2
Reducing experimental trial-and-error and speeding up the design of sophisticated structural materials depend on accurate phase prediction in high-entropy alloys (HEAs). In this work, compositional descriptors were used to categorize alloy phases using a comparative ML (machine learning) framework. Using accuracy, precision, recall, F1 score, area under the ROC curve (AUC), and tenfold cross-validation, seven supervised learning algorithms such as Random Forest (RF), Decision Tree (DT), Extreme Gradient Boosting (XGB), Gradient Boosting Classifier (GBC), Support Vector Machine (SVM), Logistic Regression (LR), and Multi-Layer Perceptron (MLP) were systematically assessed to determine their statistical robustness and predictive power. Despite the fact that a few of models demonstrated nearly flawless training performance, their testing outcomes demonstrated considerable variations in generalization behavior. With a testing accuracy of 0.9875, an AUC of 0.999, and a cross-validation score of 0.9848 with minimal variation, MLP performed the best overall. SVM and LR, which also showed good stability and dependable prediction capacity, came in second and third, respectively. While RF and particularly DT demonstrated significant overfitting, which was manifested in lower testing accuracy and larger statistical deviations, ensemble boosting techniques (XGB and GBC) demonstrated competitive accuracy (> 0.95) with marginally higher variability. Accuracy, precision, recall, and F1 score all show strong agreement, indicating little prediction bias and balanced classification across phase categories. Furthermore, SHAP-based interpretability analysis quantitatively revealed the influence and direction of key compositional and thermodynamic descriptors on phase prediction, providing physically meaningful insights and practical guidelines for alloy design. The optimized MLP and SVM model was further employed to predict the phases of five newly designed refractory high-entropy alloys (RHEAs), demonstrating its robustness and applicability for accelerating the discovery of novel alloy compositions. These results demonstrate that for materials informatics applications, statistical consistency and model generalization are more important than flawless training accuracy. The most reliable methods for data-driven phase prediction are, all things considered, neural network and kernel-based techniques, which provide a strong foundation for quickening the identification and refinement of intricate multicomponent alloys.
Thick slab continuous casting is severely constrained by internal quality defect risks and the traditional “equal-thickness” production paradigm. To break these speed bottlenecks, this study proposes a liquid core continuous reduction (LCCR) strategy. By decoupling mold casting dimensions from final slab specifications, LCCR applies substantial deformation in the high-liquid-fraction zone, utilizing mass flow balance to enable in-line gauge reduction and accelerate casting speed. To assess the crack risks associated with thinner shells, a 3D thermomechanical coupled finite element model for Q345C steel was established. Incorporating prior high-temperature tensile test data, the Normalized Cockcroft-Latham (NCL) criterion was introduced to evaluate shell integrity under multi-roll alternating stresses. Results reveal that LCCR induces deep “V”-shaped centripetal plastic deformation. Among the examined schemes, a total reduction of 30 mm increased the casting speed by 15
In this study, Stellite 6 alloy coatings were fabricated on Q235 steel via laser cladding and plasma cladding. Microstructure, elemental distribution, cross-sectional microhardness and wear properties of the resulting coatings were systematically investigated. The results show that both coatings possess sound forming quality, few defects and favorable metallurgical bonding with the substrate. The laser cladding (LC) coating shows finer grains, more uniform elemental distribution, higher microhardness and gentler hardness gradient than the plasma cladding (PC) one. Wear tests demonstrate that Stellite 6 coatings effectively improve the wear resistance of Q235 steel, and the LC coating exhibits optimal anti-wear performance. This work provides technical support for the surface strengthening of Q235 steel using cobalt-based alloy coatings.
This research work aims to investigate the impact of key operational and geometrical variables in gas atomization on the particle size fraction and morphological characteristics of copper powder. Pure copper powder was produced using a confined gas atomization system with argon as the atomizing gas. Copper ingots were melted in a 10 kg induction furnace and atomized in a pilot-scale setup. The melt temperature was varied from 1458 to 1560 K, while the atomizing gas pressure ranged from 1 to 5 MPa. Two melt delivery nozzle (MDN) configurations i.e. a conical-shaped (CMDN) and a straight (SMDN) were investigated with different protrusion lengths. Powder morphology and particle characteristics were analysed using SEM and a morphological image analyser. The findings revealed that, through optimization of process and geometrical parameters, the copper powder was produced successfully with a D50 = 94.5 µm, particle size fraction above 90
This study investigates the effect of hybrid reinforcement with alumina (Al2O3) and fly ash cenosphere on the microstructural, thermal, residual stress, interfacial, and corrosion behaviour of aluminium matrix composites. Composites were fabricated via ultrasonic-assisted stir casting followed by squeeze casting, with a fixed 2 wt.
The effects of deformation and annealing on the microstructural and mechanical properties of the Cr12Fe51Ni12Mn25 (hereinafter referred to as Mn25) alloy were systematically investigated. In the homogenized state, the alloy had coarse grains. After cold rolling deformation, partial recrystallized microstructure with texture was formed, which originated from recrystallization induced by thermal effects during plastic deformation. The complete recrystallization occurred in the alloy, accompanied by the formation of uniform equiaxed grains after annealing treatment, with random orientations. The tensile strength of the alloy was improved by 41
NiCrAl laser-clad coatings were prepared on Q235 steel at 0, 25 and 50 °C as well as 100 and 200 °C. The effects of substrate temperature on thermal behavior, microstructural evolution and coating properties were investigated. As the substrate temperature increased, heat accumulation in the cladding zone increased. The high-temperature residence time also increased. The temperature gradient, solidification rate, and cooling rate decreased overall. Visible cracks, pores, and local interfacial discontinuities were generally reduced. Interfacial continuity and elemental interdiffusion were improved. The surface microstructure evolved from fine directionally oriented dendritic and reticular features to cellular and blocky structures with relatively larger characteristic scales. The 0 °C sample showed the highest hardness. The 200 °C sample exhibited the best wear resistance. The 100 °C sample showed the best corrosion resistance. These results reveal that substrate temperature provides a practical route for balancing hardness, wear resistance and corrosion resistance in NiCrAl laser-clad coatings.
Real-time shrinkage of medium alloyed steel corresponding to third generation AHSS has been studied using an in-house developed device, under high cooling conditions. The device made of copper mold has a T-shaped cavity along with provision for water cooling. Displacement of the solidifying shell is measured by a contact-based linear variable differential transducer (LVDT). Experiments were conducted for varying alloying contents (Mn, Al etc.), and results obtained were further analyzed. Corresponding phases formed and change in volume of the system during solidification were calculated using thermodynamic software Thermo-Calc. The results suggest that increasing Mn content (within the studied range 0.5–5 Wt
This review summarizes the advancement in the use of protein–metal biopolymer nanocomposites for bone tissue engineering and highlights its potential to enhance osseointegration mechanical performance. This review focuses on the multifunctional role of proteins, collagen, and silk, along with bioactive components such as calcium and titanium, and its combination with biopolymers like chitosan and alginate for scaffolds fabrication. A systematic analysis of research and review articles of last two decades was reviewed to evaluate the preparation, fabrication techniques, and biological activity of protein/metal/biopolymer nanocomposites. Recent advancements in 3D printing and hydrogel preparation approaches for scaffold development and its use as substitute for implants is highlighted. Reviewed studies demonstrate that protein–metal biopolymer composites can promote bone cell attachment/proliferation/differentiation/mineralization, while also improving structural support for bone regeneration. However, challenges pertaining to long-term stability, immune responses, and large-scale manufacturing need to be addressed. Future research should focus on optimizing composite design that includes functional biomaterials, involving advanced functional biomaterials to accelerate clinical translation of patient-specific bone regenerative systems.
The present work integrates DEFORM-HT simulations with experimental data to evaluate the influence of tempering temperature on the microstructure, mechanical properties, and corrosion resistance of AISI 420 martensitic stainless steel. Specimens were austenitized at 1050 °C for 60 min, oil-quenched at 30 °C, and tempered at 250–650 °C for 120 min. XRD, OM, SEM, and SEM–EDS were used to track phase changes and carbide precipitation, while Vickers hardness, tensile testing, and potentiodynamic polarization in 3.5 wt.
Scan strategies are cost-effective means of mitigating residual stresses and warpage. Numerous optimized strategies have been validated for reducing residual stress in similar metal deposition. However, we still do not know if the same optimized scanning strategy used for similar metals can help reduce residual stresses in dissimilar metal deposition. In this study, a one-way coupled thermomechanical analysis has been performed using the finite element method (FEM), where SS316 steel is taken as the substrate, and copper is the clad layer. The study is performed for six scanning strategies—raster, zig-zag, alternate, out-in spiral, in–out spiral, and an S scan. The anisotropic heat transfer behavior during copper-SS cladding necessitates selecting strategies that promote homogeneous thermal distribution by ensuring that no more than 50
To optimize the composition and improve the comprehensive performance of Zn–Al–Mg coatings, Zn-1.6
