There is a high need for parts with well-balanced mechanical properties in industries. This is achieved through the use of various heat treatment processes. The adjustment of heat treatment parameters can lead to a diversity of microstructures. The heat treatment parameters of cooling, such as furnace, air, oil, and water cooling, as well as the soaking time, play important roles in determining the characteristics of microstructures obtained. The importance of these parameters is underscored by the fact that the mechanical properties of metals and their alloys, such as strength and ductility, are dependent on their microstructures. This paper presents a review of the effects of annealing, normalizing, high-temperature annealing, and solution and aging heat treatments on the microstructures and mechanical properties of Ti6Al4V, high-strength steels, and aluminum alloys. It is clear from this study that annealing coarsens the microstructural features, reduces hardness and strength, and increases ductility and machinability of all three different alloys considered here, while normalizing refines their microstructures and improves strength, while ductility is reduced. Evidently, heat treatment processes play an important role in the microstructure and mechanical properties of the three alloys. Therefore, structural parts with well-balanced mechanical properties needed in various industries can be achieved through the application of these heat treatment processes.
This study presents a comparative evaluation of unsupervised anomaly detection techniques using the PyOD Python library, applied to three representative industrial scenarios: Intrusion Detection, Fault Detection, and Predictive Maintenance. Three public datasets, each corresponding to one of these domains, are used to assess the generalizability and robustness of the methods. The methodology includes data normalization, feature selection, and class balancing to address the specific challenges of each dataset, such as class imbalance and heterogeneous feature spaces. Performance is assessed using metrics such as Precision, Recall, Specificity, F1-score, AUC-PR, AUC-ROC, Balanced Accuracy, and Execution Time (training and testing). The findings offer valuable guidance for selecting robust anomaly detection models in industrial applications beyond cybersecurity, including those related to reliability and maintenance. The code and results will be publicly available on GitHub https://github.com/hvelesaca/PyOD_OPC-UA to support future research.
The deformation and failure of protective covers in pyrotechnic separation devices critically affect the safety of spacecraft instruments and personnel. Current research primarily addresses the shape and fracture mechanisms of protective covers, but the effects of thickness and material remain unclear. This study first established a fluid-structure coupling simulation model to replicate the entire process from ignition of the shaped charge to the cutting and separation of the Carbon Fiber Reinforced Polymer (CFRP) composite separation plate. It then compared the effects of six protective covers of varying thicknesses, made of aluminum alloy and stainless steel, on the separation plates. Finally, a cutting experiment was conducted to validate the simulation results. The conclusion shows that the delamination of the composite separation plate will not be significantly different due to changes in the material and thickness of the protective cover. The delamination degrees of the separation plate in simulation (t = 20 µs) and experiment are 20.66% and 46.71% respectively. This discrepancy is primarily due to differences in the locations where characteristic points are extracted and the simulation properties at the km/s scale. In addition, based on the lightweight requirements of aerospace structures and the deformation of the protective cover, it is recommended that a 3 mm thick aluminum alloy protective cover is more suitable for a 3 mm thick composite separation plate with weakening grooves and the deformation of protective cover is 9 mm. These findings offer valuable insights and guidelines for the practical design and optimization of shaped-charge separation devices, enhancing their reliability and performance in aerospace applications.
Scalable manufacturing of titania nanotube (TiO2 NT) coatings for orthopedic implants requires robust control of electrochemical anodization and post-anodization thermal processing under production-relevant conditions. While TiO2 nanotube surfaces have shown promising biological performance at a laboratory scale, industrial translation is constrained by challenges associated with electrolyte reuse, process reproducibility, and annealing throughput. This study addresses these bottlenecks through a combined experimental and process-modeling approach focused on manufacturability rather than biological validation. Three anodization workflows, an optimized ethylene glycol-based ammonium fluoride process, a conventional EG + NH4F baseline, and an HF aqueous baseline, were benchmarked on additively manufactured Ti–6Al–4V substrates produced by direct metal laser sintering and electron beam melting. The optimized process produced larger nanotube diameters (108 ± 9.6 nm), higher anatase fraction after short annealing (84.9 ± 1.7%), and improved process yield (90.7 ± 2.3%) relative to baseline methods. Electrolyte reuse experiments revealed predictable fluoride depletion and accumulation of dissolved metallic species with increasing processed area; filtration removed particulates but only a limited fraction of dissolved ions. A simple predictive fluoride depletion model was therefore developed to enable proactive replenishment during reuse. Implant-scale furnace modeling showed that direct energy cost per implant is low, while throughput is governed primarily by cycle time. Overall, the study provides a practical framework for electrolyte lifecycle management and high-throughput thermal processing, supporting industrial-scale production of TiO2 nanotube-coated orthopedic implants.
To improve machining efficiency, this paper investigates the path optimization problem in numerically controlled drilling of printed circuit boards. The traditional Traveling Salesman Problem model exhibits significant limitations when applied to circuit boards characterized by high density and repetitive hole patterns. By analyzing spatial distribution features such as cluster distribution and module reuse of the holes, a hybrid path optimization algorithm is proposed. This method identifies holes with regular distributions and clusters them as macro operation units. A hierarchical optimization strategy is then adopted, performing inter-zone optimization first followed by intra-zone optimization. Decomposing the large-scale Traveling Salesman Problem into multiple smaller sub-problems significantly reduces computational complexity. By integrating the optimization of cluster entry/exit points with the 2-opt algorithm, a holistic optimization of both global and local paths is achieved. Simulation experiments demonstrate that the proposed method significantly reduces both the total drilling path length and computation time compared to conventional optimization methods.
Light, as a pivotal and versatile energy source, has given rise to a multitude of additive manufacturing (AM) technologies, collectively termed light-derived additive manufacturing (LDAM). This review provides a critical overview of recent advances in four principal categories: Laser Powder Bed Fusion (LPBF), Vat Photopolymerization (VPP), Laser Direct Writing (LDW), and Laser Metal Deposition (LMD). For each technology, we dissect the underlying principles, highlight groundbreaking studies and identify persistent challenges such as defect control in LPBF, material limitations in LMD, and speed-resolution trade-offs in VPP and LDW. The review further offers a unique comparative analysis through technology selection maps, guiding researchers in choosing the appropriate light-based AM process for their specific material and performance requirements. It aims to provide an overview of the current advances of research in this area, identify the still existing challenges and assess the trends and solutions related to specific studies. It expects that this review will prove invaluable reference to researchers and practitioners of AM technology, and that our efforts in this evolving area will contribute to the further advancement of AM.
This review traces the evolution of low-density steels (LDS) and highlights the key mechanisms that link processing routes to microstructural evolution and performance. Beyond fabrication methods, the article emphasizes the fundamental insights that have emerged, particularly the roles of metal carbide/intermetallic network control, segregation mitigation, and grain refinement that govern the unique behavior of LDS across processing routes in achieving superior mechanical behavior. A key insight from the literature is the exceptional potential of mechanical alloying combined with spark plasma sintering to produce ultrafine and highly homogeneous LDS microstructures that are unattainable through traditional melting routes. The review also identifies the emerging role of near-net-shape casting and additive manufacturing as transformative technologies capable of overcoming longstanding challenges related to defects, compositional inhomogeneity, and geometric limitations. Overall, the review emphasizes that optimized processing strategies and parameter control will be crucial to enhance efficiency, unlocking superior mechanical properties and realizing the full lightweight potential of LDS in advanced engineering applications.
Medium manganese steels provide numerous benefits in hot forming, including reduced blank reheating temperatures and critical quenching rates compared to conventional boron-added steels. Moreover, their enhanced strength and ductility make them a promising material for lightweight components in the mobility sector. In this study, the flow behaviour of a novel medium manganese steel is characterised and modelled to enable the simulation of hot forming processes. A forming and quenching dilatometer is utilised for isothermal tensile tests at different forming temperatures and strain rates. The specimens undergo heat treatment prior to forming, following a process route that includes annealing, cooling, and reheating to replicate the heat treatment at the steel producer and the hot forming at the parts manufacturer. An in-situ optical measurement system is used to determine the strains with digital image correlation. The experimental flow curves are modelled using various phenomenological hardening laws. Finally, the applicability of the hardening laws is verified by the simulation of a tensile test that was not used for modelling. The best prediction accuracy was achieved by the modified Norton-Hoff law, which provided a root mean square error of 14.4% during model calibration and a low mean absolute percentage error of 1.3% during validation.
This paper presents the effect of work material on the formed shape in a cylindrical deep drawing using a die with circumferentially varying die radius dimensions. In the deep drawing, the material anisotropy causes unevenness, called “ears”, on the cup edge. Because of the additional trimming process, the occurrence of earing leads to material loss and additional production processes, resulting in low productivity. The earing suppression has usually been conducted by material development to suppress material anisotropy. It has been shown that a die with different die radius dimensions has been proposed, and that the ear shape can be changed by the die only. However, the effects of material thickness, diameter, and anisotropy on the formed shape have not been reported. In this paper, the effects of forming conditions of mainly the material were investigated by experiments and finite element analysis in cylindrical deep drawing using a die with circumferentially varying die radius dimensions. As the sheet thickness was thicker and the blank diameter was larger, the ear height increased due to the large material inflow. Stainless steel, aluminum alloy, and copper materials can be used to suppress ear height if appropriate forming conditions are set. It has also been clarified that there are conditions of die placement that suppress the ear height in correlation with the in-plane anisotropy of the material.
The hole expansion behavior serves as a key metric for assessing the formability of automotive structural components containing holes. With the growing emphasis on decarbonization in automotive manufacturing, hot-rolled steels have gained attention as promising substitutes for cold-rolled counterparts. Owing to their thermomechanical processing characteristics, hot-rolled steels frequently exhibit banded microstructures oriented along the rolling direction; however, the effect of these banded structures on hole expansion behavior remains insufficiently understood. In the present work, two hot-rolled steels with distinct banded morphologies were investigated under punching conditions in accordance with ISO 16630. The study focused on the evolution of microstructural features within the shear-affected zone (SAZ) and at the hole-edge surface before and after hole expansion. The findings indicate that the banded arrangement facilitates circumferential crack propagation along the hole edge, thereby improving hole expansion performance. This advantageous effect is particularly evident when the fracture zone constitutes a large fraction of the hole-edge surface, promoting stress relief through the generation of cross cracks. In contrast, when the fracture zone is limited, fracture initiation in the burr zone at the hole periphery leads to visible hole expansion cracks, contributing to the safe identification of failure during service. Additionally, the matrix hardness and strength were found to play a decisive role in governing hole expansion behavior, with a positive correlation established between edge hardening induced by punching and the hole expansion ratio.
With the rapid increase in chip computing power, the heat flux density has sharply increased, becoming one of the bottlenecks restricting chip performance. This study presents a synergistic approach to thermal management by integrating a bioinspired spider-web microchannel heat sink with intelligent optimization. A multi-objective particle swarm optimization algorithm was employed to systematically optimize channel geometry, maximizing heat transfer while minimizing pressure loss. The TOPSIS-based decision-making identified an optimal solution that increases the convective heat transfer coefficient by 35.2% while reducing pressure loss by 8.3%. And, this advantage is particularly evident at 320 W/cm2, with a maximum temperature reduction of 9.68 K. It means that the proposed structure significantly enhances both thermal and hydraulic performance compared to conventional designs, with improvements becoming more pronounced under increasing heat flux. Finally, the diamond/copper composite material was used to prepare the microchannel heat sink, and the heat dissipation performance of the designed biomimetic heat sink was verified by loop test. This work demonstrates the strong potential of combining bioinspired design with intelligent optimization for advanced thermal management in high-heat-flux applications.
This paper innovatively proposes a combined process combining ultrasonic vibration (abbreviated UV) with creep age forming (abbreviated CAF), named UVCAF, for high-quality forming of dissimilar 7055-T6/2197-T8 FSWed T-stiffened plates. And based on this, a multi-objective optimization quality comprehensive evaluation model of the AMOGA-EWM algorithm is proposed, obtaining the optimal process parameter solution combination as [164.8 °C, 9.2 h, 9.6 μm]. The reliability and feasibility of the above evaluation model in improving the forming rate and mechanical properties for the T-stiffened plates are verified. Meanwhile, through comparative analysis of the experimental results of UVCAF under the optimal process parameters, it is found that the forming rate, tensile strength, and elongation of T-stiffened plates under UVCAF are 5.4%, 12.3 MPa, and 0.82% higher than those under CAF. In addition, the microscopic analysis results indicate that the fracture mode of the specimens under CAF and UVCAF is a ductile fracture, and the weld nugget zone of the specimens under CAF and UVCAF is the combined reinforcement of the T1 and η phase. However, the introduction of UV through the strengthening effect of fine grains makes the η phase more abundant in UVCAF specimens, thereby improving the forming accuracy and performance of the specimens.
Magnetorheological materials, as a type of intelligent controllable material, have broad application prospects in the engineering field. However, stability issues (such as sedimentation, particle agglomeration, and extreme temperature adaptability) severely limit the practical application of magnetorheological materials. In this paper, the research progress on the stability of magnetorheological materials was summarized and categorized, and analyzed from three aspects: material systems, testing methods, and improvement strategies. First, the compositional characteristics and stability challenges of magnetorheological materials with different matrix morphologies were compared, and it was pointed out that sedimentation issues in magnetorheological fluids and particle migration issues in magnetorheological elastomers are key research focuses. Second, the currently available stability testing methods were summarized, including sedimentation observation, particle concentration testing, redispersibility testing, and temperature stability testing, and the applicable scenarios, advantages and disadvantages of different methods are discussed. Third, the technical measures to enhance stability were discussed in detail, such as additive optimization (surfactants, thixotropic agents, nanoparticles, etc.), magnetic particle surface modification (polymer coating, composite structure design, etc.), and matrix carrier modification (magnetic matrix carriers, fluid-solid carrier conversion, etc.), and the enhancement mechanisms and characteristics of different methods were compared. Finally, current research limitations in terms of performance trade-offs and long-term reliability were identified, and future directions such as smart responsive materials and standardized testing were proposed. This study provides theoretical references and technical guidance for the stability design and engineering applications of magnetorheological materials.
Driven by the need for high-performance thermal barrier coatings (TBCs) in geothermal power generation, (Gd x Yb 1 -x ) 2 Zr 2 O 7 ceramics ( x = 0.5, 0.7, 0.9, 1) were synthesized via the solid-state reaction method. Their crystal structure (XRD), microstructure (SEM), mechanical properties (hardness, fracture toughness, Young's modulus), and thermal properties (diffusivity, conductivity) were systematically characterized to investigate the impact of Yb 3+ doping. Major findings include: (1) All compositions exhibit a stable fluorite structure from room temperature to 873 K. (2) Yb 3+ doping significantly reduces thermal conductivity, with the x = 0.7 composition achieving the minimum value of 0.858 W · m −1 · K −1 at 675 K (>30% lower than YSZ). (3) Doping enhances hardness and fracture toughness, peaking at 10.1 GPa and 2.23 MPa · m 1/2 for the x = 0.5 composition. (4) Young's modulus shows a non-monotonic trend with doping. This work demonstrates that Yb 3+ -doped Gd 2 Zr 2 O 7 , particularly the x = 0.7 composition with ultralow thermal conductivity and sufficient mechanical strength, presents a promising candidate material for medium-high temperature (300–873 K) TBCs in geothermal applications, offering new avenues for durable coating design.
Assessing and predicting formability of a material have significant importance for forming process design and optimisation. In this paper, formability of AA6082 under various conditions were investigated through biaxial tensile tests, and the results were used for calibrating a set of constitutive equations based on continuum damage mechanics (CDM). Forming tests that replicate industrial forming conditions were conducted to explore the effects of HFQ conditions on the formability of the AA6082 aluminium sheet. In these tests, B-pillar components of a commercial vehicle were produced under different conditions, followed by ARGUS measurements to capture the formed geometry and strain distributions. The CDM-based constitutive equations were implemented into FE model to simulate the forming processes, and the simulation results were compared with experimental data to validate the model. It was found that lower forming speed and higher temperature lead to higher formability of the material and are beneficial to the quality of the formed components. Numerical simulations successfully predicted the strain distribution and defects formed during forming and showed good agreements the experimental results from the B-pillar forming tests, indicating that the CDM-based model can be successfully applied in practical forming processes for designing and optimising the process parameters.
The progressive forming of sheet metal through stages such as blanking, deep-drawing and ironing is an economically attractive route to complex components. Wear control is decisive for product quality, as it prevents defects and minimizes scrap. Optical sensors are increasingly supplementing conventional monitoring, thanks to ongoing digitization and continuous improvement of availability. This paper introduces a modular, adaptive, camera-based measurement stage that captures component geometry and delivers cause-specific feedback on tool wear, enabling anomalies to be linked to individual forming steps. The system employs photometric stereo analysis: several images are taken under different illumination angles. A normal map is reconstructed, and pixel-wise brightness differences reveal the surface topology. Deviations from target geometry are then localized by comparing actual and nominal data. A key contribution of the present work is the systematic investigation of highly reflective workpiece materials-in contrast to previous studies based on CR DC04 steel, whose matte finish approximates Lambertian behavior. Specular surfaces, such as the ETSR TS245, distort the incident light field, violating this assumption and reducing detection accuracy. Therefore, it is necessary to analyze how variations in reflectivity and surface finishes influence the photometric stereo pipeline. In addition, calibration and illumination strategies are proposed that restore reliable anomaly detection even for glossy substrates. This study lays the groundwork for efficient, robust and adaptive manufacturing systems by providing process insights without disrupting production and addressing the challenges posed by non-Lambertian reflections. It advances intelligent forming technology across varying materials in manufacturing processes.
During the laser welding process of aluminum alloy, the high reflectivity of aluminum alloy to laser and the severe fluctuation of the keyhole lead to highly unstable energy absorption, which readily induces defects such as spatter and porosity. Furthermore, the multi-physical field coupled dynamic behaviors within the molten pool, involving heat transfer, fluid flow, phase transformation, and element evaporation, are difficult to capture and quantify, resulting in a lack of precise theoretical guidance for this process. To address these issues, a multiple-reflection laser absorption model for the keyhole in the aluminum alloy laser welding molten pool was established. Basic assumptions were applied to the laser welding process to simplify the calculation of the molten pool mathematical model. The governing equations for the laser welding molten pool were established. Finally, the laser welding molten pool process was simulated. Experimental results demonstrate that employing a laser incident angle of 30° reduces the molten pool flow velocity by approximately 40%, effectively suppressing the spatter phenomenon. When the welding speed is increased to 8.0 m/min, the escape efficiency of molten pool bubbles is enhanced by 50%, and the uniformity of element diffusion is significantly improved. The comprehensive optimization of parameters can improve weld formation quality by more than 35%. The study provides an effective numerical analysis tool for understanding keyhole dynamics and molten pool behavior in aluminum alloy laser welding, significantly enhancing the comprehension of defect formation mechanisms. The established models and optimization results can offer a theoretical basis and parameter design guidance for the development of high-quality and high-efficiency aluminum alloy laser welding processes.
In order to advance sustainability in manufacturing, it is necessary to reduce both energy use and material waste. Tribology is recognised as a central factor in this effort. In sheet metal forming, for example, friction and wear lead to increased energy demand, tool degradation and lubricant consumption. Therefore, surface texturing has emerged as a promising strategy to improve tribological efficiency, contributing to both technical performance and reduced environmental impact. Building on earlier findings which identified cavity geometry, spatial distribution and load conditions as decisive parameters, this study introduces a systematic methodology for designing surface textures for lubricated forming operations. Computational fluid dynamics is used to analyse the rheological mechanisms underlying lubricant flow and pressure generation in textured interfaces. The optimal cavity design is defined by its ability to minimise the coefficient of friction. The results demonstrate that lubricant reservoirs and hydrodynamic pressure formation depend heavily on cavity dimensions and distribution. In particular, the coverage ratio and lubrication clearance are shown to have the most significant influence on friction reduction. These insights pave the way for more resource-efficient and sustainable sheet metal forming processes by linking tribological performance to reduced energy demand and extended tool life.
Driven by the need for high-performance thermal barrier coatings (TBCs) in geothermal power generation, (GdxYb1-x)(2)Zr2O7 ceramics (x = 0.5, 0.7, 0.9, 1) were synthesized via the solid-state reaction method. Their crystal structure (XRD), microstructure (SEM), mechanical properties (hardness, fracture toughness, Young's modulus), and thermal properties (diffusivity, conductivity) were systematically characterized to investigate the impact of Yb3+ doping. Major findings include: (1) All compositions exhibit a stable fluorite structure from room temperature to 873 K. (2) Yb3+ doping significantly reduces thermal conductivity, with the x = 0.7 composition achieving the minimum value of 0.858 W m(-1 ) K-1 at 675 K (>30% lower than YSZ). (3) Doping enhances hardness and fracture toughness, peaking at 10.1 GPa and 2.23 MPa m(1/2) for the x = 0.5 composition. (4) Young's modulus shows a non-monotonic trend with doping. This work demonstrates that Yb3+-doped Gd2Zr2O7, particularly the x = 0.7 composition with ultralow thermal conductivity and sufficient mechanical strength, presents a promising candidate material for medium-high temperature (300-873 K) TBCs in geothermal applications, offering new avenues for durable coating design.
Rotary burrs made of WC-8Co cemented carbide are widely used in automated filing systems, yet rapid cutting-edge wear significantly limits their performance. For this purpose, coupled electromagnetic treatments were applied to the WC-8Co cemented carbide region of rotary burrs to enhance their cutting performance. Four key performance parameters were evaluated: average cutting-edge wear, cutting-head diameter wear, average machining depth, and material removal amount. The cutting performance and the resulting surface roughness of workpieces machined with treated and untreated burrs were compared. As a result, under optimal conditions (0.6 T magnetic field and 1.2 V electric field), coupled electromagnetic treatment reduced average cutting-edge wear and cutting-head diameter wear by 15.4% and 21.4%, respectively, increased average machining depth and material removal amount by 21.3% and 25.2%, respectively, and decreased the surface roughness of the machined workpieces by 36.2%. The study through experimental and numerical analysis confirmed that these enhancements in cutting performance are largely attributed to the increased thermal conductivity and hardness of the treated burrs, which result from reductions in magnetic domain walls and increases in crystal defects induced by the coupled electromagnetic treatment. Such changes collectively suppressed adhesion wear, oxidation wear, and abrasive wear, thereby enhancing the tool's cutting performance.
