•Zein promoted the aggregation of KGM chains in KGM/zein blend solution.•Zein particles grew larger but were homogeneously distributed during drying.•KGM/zein blend solution gradually formed a weak ...gel after 2 h of drying at 60 °C.
During film formation at 60 °C, the microstructure and rheological properties of konjac glucomannan (KGM) film-forming solution and KGM/zein blend film-forming solution were investigated. The drying process of film-forming solutions was divided into two stages according to the drying curves. Scanning electron microscopy showed that KGM chains in the blend solution aggregated into thicker chains and formed a molecular network with larger pores. Zein particles grew larger but were homogeneously distributed during drying as observed by confocal laser scanning microscopy. The addition of zein improved the thermal stability of the film-forming solution. As the drying proceeded (up to 8 h), KGM solution exhibited a typical concentrated solution behavior due to molecular entanglement; whereas the blend solution gradually formed a weak gel after 2 h. Complex viscosity data for the film-forming solutions were well-fitted by the power-law model. The information obtained from the study is important for understanding the film-forming mechanism.
Metal forming process is one of the most important manufacturing processes that translate the sheet and bulk metal to the final product with simple punch and. Single point incremental forming (SPIF) ...process is considered as a modern flexible manufacturing techniques that is use a simple tool and non-specific fixture die to complete the forming, this method is used in prototype manufacturing system due to the time consuming during the forming. The advantage of this process is low cost and simple equipment. However, some limitation was founded including poor geometric accuracy, non- uniform thickness distribution, dimple and high forming time. Multi-point forming (MPF) is another modern forming method that is used in industrial applications due to its advantage such as uniform thickness distribution with low forming time consuming. This method used matrix of simple tools to deform the sheet metal to the desired shape. Wrinkle and dimple due to small contact area between tool and blank under high forming force are considered the main limitation of using MPF process. To take the advantages of this processes with reduced the limitations a hybrid forming (HF) process of both MPF and SPIF are used. The experimental work was applied to produce a hemi-spherical product of brass blank using the SPIF, MPF, and HF processes. Satisfactory results are obtained using a hybrid forming process with free of defects products and reduction in production as compared to the SPIF. A high improve in microstructure including refinements in grain size with twins effects. The sample produced with SPIF process showed a high microhardness as compared to the sample produced using MPF process, however, the hybrid MPF and SPIF forming process showed slightly improving in microhardness as comparing to the as received materials, reflecting the microstructure development of the processed samples.
Pure copper has excellent conductivity but low strength, which greatly limits its application in many fields. In recent years, developing high-strength and high-conductivity (HSHC) copper alloys has ...been gaining increasing traction. Copper-iron (Cu-Fe) alloys hold great application potential in power, electronics, communications, railway transportation and other industries due to their cost-effectiveness and comprehensive plasticity. In this review, we begin with a brief analysis of two primary factors that limit the development of HSHC Cu-Fe alloys. We then summarize the major results on how to enhance the strength, conductivity, and electromagnetic shielding performance of Cu-Fe alloys by improving the forming processes and adjusting the microstructure evolution and highlight the underlying strengthening mechanisms. We close by providing new insights into the application prospect and future research directions of Cu-Fe alloys with both high strength and conductivity.
•Forming process of Cu-Fe alloy was comprehensively evaluated, with specific recommendations for enhancing each approach.•Effect and mechanism of the addition of Fe and the tertiary alloy elements were analyzed.•Evolution of microstructure and properties of Cu-Fe alloy during different deformation is summarized.•Strengthening mechanisms of mechanical properties and EC are discussed.•Insightful information on developing high-strength, good-conductivity and diversefunctionality Cu-Fe alloys is provided.
Increasing throughput in wind turbine blade production can be achieved by separately manufacturing pre-shaped binder-stabilised dry preforms, and subsequently placing them in the blade mould. To ...avoid manufacturing defects, a trade-off between the formability and the handleability of the preform is necessary. In this paper, an experimentally validated preform model is used to study how variations in material properties, tool geometry, and placement tolerances influence defect generation. The results from three studies are presented. In the first study, a preform is formed over a ramp transition with variations in geometry. The results from this study indicate that a short ramp promotes transverse shearing of the preform. In the second study, the material properties of the preform are varied. The results indicate that a high mode I cohesive law of the binder and a high bending stiffness of the fabric promote transverse shearing and remove wrinkles. In the last study, placement tolerances for a pre-shaped preform are studied. The results show that if the preform can shear between the preform edge and the tool edge, it can conform to the mould even with large placement offsets. Process engineers and blade designers can readily use these results to help reduce forming-induced wrinkles.
This paper proposes an innovative multi-scale method for determining gas pressure parameters of superplastic forming, which is based on the quantitative relationship between the grain growth ...mechanism and fracture mechanism of Ti-6Al-4V alloy. The high-temperature tensile tests were conducted on the material at temperatures ranging from 700, 800, 840, 890, 920, and 950°C, strain rates were selected as 10-2∼10-4/s. The grain size measurements were observed using electron back-scatter diffraction (EBSD). Particularly, the relation between grain size changes and fracture behaviour is specifically discovered using a physically-based dynamic material model (DMM), and the grain size thresholds for each forming limit are proposed. The physical fracture mechanism is named the "Grain growth based fracture (GGBF)" mechanism. Furthermore, an innovative method based on the GGBF mechanism is proposed to design the superplastic forming loading, and practical four-layer hollow structures experiments are applied to validate the fracture mechanism in superplastic forming. In total, A superplastic forming GGBF mechanism has been verified, and it is expected to be helpful for shape and property control in the forming process of complex structures.
•An innovative multi-scale method for determining gas pressure parameters of superplastic forming, which is based on the quantitative relationship between the grain growth mechanism and fracture mechanism of Ti-6Al-4V alloy;•The relation between the grain size and fracture behavior has been discussed, and the fracture mechanism is named as "Grain growth based fracture (GGBF)" mechanism;•A practical four-layer hollow structure are performed, and the new multi-scale strategy is applied to determine the gas pressures.
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•Multiple generations of amphiboles were distinguished in the Haobugao deposit.•Amphiboles in the Haobugao deposit were formed from a fluid mixing magmatic fluid with meteoric ...water.•Amphibole geochemistry is useful for tracing fluid evolution and mineralization processes.
The Haobugao Zn-Fe-Sn deposit is a typical skarn deposit in the southern Great Xing’an Range of NE China. Despite many advances in understanding its genesis, the detailed ore-forming processes of Zn, Fe and Sn are still unclear. Amphibole, a rock-forming mineral, has been well studied as an indicator of diverse magmatic and metamorphic processes; however, the geochemistry of hydrothermal amphibole has previously received less attention. The Haobugao deposit contains two generations of hydrothermal amphibole (Amp-I and Amp-Ⅱ), which provides a good opportunity to use amphibole geochemistry to trace the mineralization process. Early Amp-I coexists with cassiterite, magnetite and quartz, whereas late Amp-II coexists with quartz and sulfides and can be further divided into two subgroups: Amp-Ⅱa (in skarn) and Amp-Ⅱb (in the country rocks of siltstone). The oxygen isotopic compositions of the fluid (δ18Ofluid 2.9‰) responsible for the Amp-I formation indicate that the amphiboles formed from mixed magmatic fluid with meteoric water. Amp-I is LREE-depleted and HREE-enriched with obvious negative Eu anomalies. Amp-Ⅱ is generally slightly LREE-depleted with negative or positive Eu anomalies and positive Ce anomalies. The incorporation of trace and rare elements is mainly controlled by the fluid composition. Detailed petrological observations and amphibole geochemistry, combined with previous research results, confirm that Sn, Fe, Pb and Zn mineralization occurred during a single mineralization event. From the oxide to the quartz sulfide stage, the ore-forming fluid evolved from high-temperature and oxidized conditions with enrichment of Sn, Li, Be and REEs to low-temperature and reduced or oxidized conditions with enrichment of Cu, Co and Zn. The concentrations of Cu, Co and Zn in different amphiboles vary with the mineral crystallization sequence. This study shows that amphibole geochemistry can be useful for tracing fluid evolution and mineralization processes in hydrothermal systems.
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•Temperature, fO2, and compositions of fluids control trace element occurrence in sulfides.•Gold occurrence is invisible as solid solution and visible as micron-sized ...electrum.•Incorporation mechanisms of invisible gold are different by structurally bound gold.•Prolonged interaction generates Cu (–Au) mineralization in IOCG-like deposits.
Gold (e.g., electrum) has been reported in the Paleozoic Heijianshan Fe–Cu (–Au) or iron oxide–copper–gold-like (IOCG-like) deposit in the Eastern Tianshan, but relationships between gold occurrence and sulfides are unclear. The Heijianshan Fe–Cu (–Au) (or IOCG-like) deposit underwent five alteration and mineralization stages: Pre-ore epidote alteration (Stage I), syn-ore magnetite/iron mineralization (Stage II) followed by pyrite alteration (Stage III) and Cu (–Au) mineralization (Stage IV), and post-ore late veins (Stage V). This deposit mainly has two types of pyrite (A and B) based on pyrite–hematite and pyrite–pyrrhotite–chalcopyrite assemblages. They are euhedral to subhedral and mainly homogenous, with the former having porous or inclusion-rich domains. Trace elements incorporating into pyrite at Heijianshan are mainly controlled by compositions (e.g., As, Co, and Cu), temperature (e.g., Ni and Se), and oxygen fugacity (fO2; e.g., As and Se) of hydrothermal fluids, respectively. The time-resolved depth-concentration profiles suggest trace elements in pyrite and chalcopyrite occur as solid solution (e.g., Co, Ni, Zn, As, and Se) and micro- to nano-sized mineral inclusions (e.g., Cu, Bi, and Pb). The gold occurrence at Heijianshan is invisible as solid solution in Stage III pyrite and Stage IV chalcopyrite and visible as micron-sized Stage IV electrum. Moreover, incorporation mechanisms of invisible gold are Au3+ substituting iron or copper in pyrite A and chalcopyrite, respectively, and Au+ incorporating into the vacancy or defect positions of pyrite B. Sulfides texture and geochemical compositions when combined with previous in-situ sulfur isotope suggest that pyrite formation was resulted from interaction between external basinal brines and altered host rocks under different temperature and fO2 conditions. Ongoing fluid-rock reaction led to formation of chalcopyrite ± electrum veins as Cu (–Au) mineralization at Heijianshan. This study suggests that the prolonged interaction contributes to sulfide formation and Cu (–Au) mineralization in these Paleozoic Fe–Cu or IOCG-like deposits formed in basin-related setting, and the Aqishan-Yamansu belt, Eastern Tianshan has gold mineralization potential.
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•Hamaling deposit is the first gold-copper-molybdenum deposit discovered in the Ordovician strata in the Tongling district, eastern China.•Hamaling deposit is developed porphyry-type ...ore in granodiorite, skarn-type ore at contact zone and breccias-type ore in Ordovician strata.•Hamaling deposit is associated with early Cretaceous magmatic activity in the Tongling district.•Hamaling deposit demonstrates a huge mineral exploration potential of the Lower Paleozoic strata in the Tongling district and even in the eastern China.
The Hamaling deposit represents the first discovery of a gold-copper-molybdenum deposit situated within the Ordovician strata of the Tongling ore-cluster region. It comprises three distinct types of ore, including porphyry-type Cu-Au ore found in granodiorite, skarn-type Cu-Au ore at the contact zone, and breccia-type Mo-Cu ore within the Ordovician strata. However, the exact mineralization age, ore genesis, and mineralization processes of the Hamaling deposit remain uncertain. To address these uncertainties, the present study employed LA-ICP-MS to date zircon in granodiorite and garnet in skarn, revealing ages of 139.3 ± 0.44 Ma and 142.3 ± 0.89 Ma, respectively. Additionally, the age of 140.0 ± 1.1 Ma was obtained through Re-Os dating of molybdenite from breccia-type ore. These findings suggest a connection between the Hamaling deposit and the early Cretaceous magmatic activity in the Tongling region. The granodiorite intrusion exhibits a high-potassium calc-alkaline affinity and formed under oxidized conditions at temperatures ranging from 721 to 832 °C (average 769 °C). The Hf isotope composition of the granodiorite implies its formation through the mixing of mantle-derived magma from an enriched lithospheric mantle with partially melted lower crustal source magma. The sulfur isotopes found in the ore minerals range from δ34S = 5.55 ‰ to 11.99 ‰, indicating a magmatic sulfur source. The H-O isotopic compositions of quartz during the quartz-sulfide stage suggest that the magmatic water was the primary component of the fluids responsible for ore formation, possibly with some contribution from meteoric water. The identification of the Hamaling deposit highlights the significant potential for mineral exploration within the Lower Paleozoic strata in the Tongling ore-cluster area and even the broader Middle-Lower Yangtze River Valley Metallogenic Belt (MLYB).
In the hot-rolling metal forming process, the consistency and accuracy of the thickness of the metal strip are the most important factors for the product quality control. The current method of ...utilizing a mechanism prediction model with pre-defined parameters does not perform well due to some limits on the model assumptions and environmental interference. Manually tuning these parameters of the mechanism model may even result in worse performance. To resolve this problem, an advanced randomized learner model, termed stochastic configuration network (SCN), is employed to build a data-driven prediction model which can be trained by using a dataset collected from a real-world hot-rolling production site. Based on the rolling theory and gray relational analysis (GRA), 36 features are selected as the inputs of the prediction model. Experimental results with comparisons show that our proposed method is feasible and outperforms other machine learning methods, such as deep learning models and the random vector functional link (RVFL) model.
To address the materials processing challenges resulting from high levels of heat input in wire arc additive manufacturing (WAAM), a novel wire arc metal additive manufacturing method using pulsed ...arc plasma (PAP-WAAM) was developed in this study. In this method, the pulsed arc plasma generated by the pulsed voltage was used as the heat source. Owing to the applied pulsed voltage, the arc plasma was alternately ignited and extinguished during additive manufacturing. By adjusting the relative positions of the tungsten electrode, filler wire, and substrate, the arc plasma was ignited between the tungsten electrode and the filler wire. This increased the proportion of discharge energy allocated to the filler wire, thus reducing the overall heat input required for material deposition. Furthermore, no heat was transferred to the deposited material because the arc plasma was extinguished during the discharge interval. Consequently, the previously deposited material was rapidly cooled. Preliminary experimental results showed that the newly developed PAP-WAAM process used 37 % less heat input than the conventional gas tungsten arc welding-based WAAM (GT-WAAM) process at the same wire feed speed of 350 mm/min. The PAP-WAAM process yielded smaller melt pools, higher cooling rates, and less heat accumulation than the GT-WAAM process, which was mainly attributed to the combined effects of low heat input and efficient heat dissipation by the pulsed discharge during PAP-WAAM. As a result, PAP-WAAM produced finer geometric features and microstructures as well as greater tensile strength than GT-WAAM.
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•A wire-based AM method using pulsed arc plasma generated by pulsed voltage as a fusion source was proposed.•The newly developed process used 37 % less heat input than the GT-WAAM process at the same wire feed speed of 350 mm/min.•The mechanisms for the reduced heat input required for material deposition during PAP-WAAM was investigated.•The influencing mechanisms of thermal behaviors on microstructural evolution and mechanical properties were investigated.
