Metal Volume Research Articles

Probabilistic buckling assessment and reliability of fiber-metal laminate, composite and aluminum cylindrical panels under compression with load and fabrication uncertainties

The objective of this article is to study the buckling behavior and reliability of fiber metal laminated (FML), composite and aluminum cylindrical panels under uniaxial compression taking into account fabrication and loading uncertainties. A 3D finite element modeling with ANSYS software has been implemented for this purpose. The panels are discretized using shell elements and the eigenvalue buckling analysis is conducted for the prediction of elastic buckling. The influences of load and fabrication uncertainties on the buckling load factor are studied with probabilistic analyses and the reliability of the panels is calculated. It is found that the thickness of aluminum layers is the most significant uncertain variable for the critical buckling load factor of FML panels, whereas the fiber misalignment angle of their composite layers is insignificant. As the metal volume fraction decreases, the sensitivity of the elastic buckling load factor to variations of the axial load distribution is reduced whereas its sensitivity to variations of the thickness of composite layers is increased. Consequently, the metal volume fraction is an important design parameter for the uncertain buckling behavior of the panels.

Fundamentals of Ultrasonic Treatment of Aluminum Alloys

High integrity cast aluminum components require the use of molten metal processing technologies prior to casting. These include processes such as degassing to reduce porosity, filtration to reduce inclusion content, addition of grain refiners to refine the grain structure, and the addition of chemical modifiers to alter the morphology of eutectic phases. Ultrasonic treatment (UST) is a novel processing method through which ultrasonic energy is introduced into molten metal for the purpose of degassing as well as modifying the cast microstructure. To optimize the use and applications of UST, it is necessary to examine the fundamental mechanisms and the limiting values of controlling parameters. The effectiveness of UST to perform a desired application within a molten metal is highly dependent on temperature, volume of liquid metal, and the state of the frequency in use. The mechanisms of ultrasonic energy imparted within molten metal will be discussed as well as the benefits of UST during molten metal processing.

Towards Efficient Polymeric Binders for Transition Metal Oxides-based Li-ion Battery Cathodes.

Transition metal oxide cathodes (TMOCs) such as LiNi0.8Mn0.1Co0.1O2 and LiMn1.5Ni0.5O4 have been widely employed in Li-ion batteries (LIBs) owing to superior operating voltages, high reversible capacities and relatively low cost. Nevertheless, despite significant advancements in practical application, TMOC-based LIBs face great challenges such as transition metal dissolution and volume expansion during cycling, which jeopardizes the future advance of high-voltage TMOCs. As a critical component of cathode, polymeric binder acts as a crucial part in maintaining the mechanical and ion/electron conductive integrity between active particles, carbon additives, and the aluminum collector, hence minimizing cathode pulverization during battery cycling. Moreover, Polymeric binder with specialized functions is thought to offer a new solution to enhancing the electrochemical stability of the TMOCs. Therefore, this review aims at providing a comprehensive summary of the ideal requirements, design strategies and recent progress of polymeric binders for TMOCs. Future design perspectives and promising research technologies for advanced binders for high-voltage TMOCs are introduced.

Certain investigation on feasibility of developing riser less ductile iron castings

The solidification mechanism of ductile iron is a bit complex due to the precipitation of graphite and silicon. These elements change the solidification pattern of cast iron. Density of these elements is less than iron leads to occupying more volume consequently increase the overall metal volume. There are two aspects on this increase in metal volume. One is, reducing this volume increase to reduce the creation of porosities at the earlier stage of solidification and second is, using this volume increase to remove porosity at the later stage of solidification. Proper understanding of this graphite expansion in cast iron solidification will bring insights on reducing or removing of the risers. The current study focus on correlating the net contraction and austenitic liquidus point with shrinkage. The average contraction found through this study is 1.36 % which is more than the net expansion of 0.25 % (without riser) reported in literature. The study found that properly balancing graphite precipitation, pouring temperature and mold strength can enable riserless casting of ductile iron by compensating for liquid contraction through graphite expansion.

Design and analyses on the recuperator of the high temperature PbLi experimental platform for CFETR

As a candidate blanket for China Fusion Engineering and Test Reactor (CFETR), the supercritical carbon dioxide (sCO2) cOoled Lithium-Lead (COOL) blanket is under development. To solve the key scientific issue, i.e. MagnetoHydroDynamics (MHD) effect, the high temperature PbLi experimental platform is planned for construction at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). As one of the key components in this platform, the recuperator acts as waste heat recovery and saving electricity power. In this paper, two types of recuperator are designed and analyzed, including the double-tube and hairpin. Firstly, the theoretical and empirical models are used to obtain different designs by changing the structure dimensions and arrangement, then the non-dimensional evaluation criteria is improved and adopted to determine the optimal design that has better comprehensive performance, i.e. higher heat transfer capacity, lower flow resistance to reduce pressure drop and smaller consume volume of liquid metal to increase economy. Finally, the thermal-hydraulic and thermal-mechanical analyses based on the optimal design of the 3D model are further carried out, which obtains the fields of temperature, pressure, velocity as well as stress, and the results can satisfy with the multiple requirements, i.e. outlet temperature under different operating conditions, flow distribution as well as structural strength. The design methodology and analysis results will provide useful technical and data support for the following engineering design and construction of the PbLi experimental platform.

Study of the dynamic response and damage evolution of carbon fiber/ultra-thin stainless-steel strip fiber metal laminates under low-velocity impact

Two configurations of carbon fiber/ultra-thin stainless-steel strip fiber metal laminates (CUSFML) with differing metal volume contents (35.3% and 18.2%) and carbon fiber-reinforced polymer (CFRP) composite laminates were selected for tests. The impact response and the effect of metal volume content on the impact resistance of CUSFML were assessed via experiment and FEM. Inducing damage by drop-weight test within the impact energy range of 18.60–46.23 J, two types of CUSFML and CFRP composite laminates were compared. In particular, the bearing capacity, impact deflection, failure modes, and energy dissipation were considered. The impact modeling using the VUMAT subroutine refines the relationship between energy-dissipating mechanism and damage evolution. The results indicate that CUSFML are characterized by higher impact resistance than CFRP composite laminates under low-velocity impact. The effect of metal volume content on the impact resistance increases gradually with impact energy increasing. Under 46.23 J impact, the CUSFML with higher metal volume content exhibits more concentrated damaged area with severe penetration failure, which is more dominated by metal failure features with a higher proportion of plastic energy dissipation. For CUSFML with lower metal volume content, extensive delamination and damage expansion occurs under the dominance of fiber damage behaviors.

High‐velocity ballistic response of AA 1100‐H14 based carbon‐fiber metal laminates: An experimental investigation

AbstractA detailed experimental investigation was carried out for the high‐velocity ballistic response of AA 1100‐H14 based carbon‐fiber metal laminates (FMLs). FMLs with different metal volume fractions and the same thickness of carbon‐epoxy fiber laminates were tested to examine the surface and internal damage. The ballistic performance parameters, namely % escalation in absorbed energy, specific energy absorbed, ballistic limit, specific perforation energy, first cracking energy, and global deformation profile, were studied and a comparison was drawn with pure carbons fiber reinforced epoxy composite laminates. Despite having greater thickness, pure carbon fiber‐reinforced epoxy composite laminates absorbed less impact energy than FMLs and failed catastrophically. For FMLs, the % escalation in the absorbed energy and the specific energy absorption kept increasing with the increasing impact velocity until the onset of perforation. Once the perforation started, both these parameters showed a decreasing trend. Thick FMLs absorbed a good amount of energy, leading to projectile recoil suffering minimal damage. The ballistic velocity, specific perforation energy, and first cracking energy on the front and rear face of FMLs layers showed an increasing trend. The minimum for the thinner and maximum for the thicker FMLs attributed to the large thickness and more metal volume fraction. Contrary to the large deformation of the impacting points, pure carbon fiber‐reinforced epoxy composite laminates showed very minimal deformation as compared to FMLs. The brittle nature of the epoxy resin resisted the deformation to a large extent leading to less energy absorption.Highlights High‐velocity ballistic response of AA 1100‐H14 based carbon‐FMLs was investigated. Ballistic performance parameters of FMLs were studied and was compared with carbons fiber reinforced composite laminates. The ballistic limit of FMLs showed a direct dependence its thickness and metal volume fraction. In the absence of any metallic layer, pure carbons fiber reinforced composite laminates absorbed less impact energy.

Influence of deformation degree on grains size and borders between them in metal alloys during cold rolling of sheets

The internal structure of metal products was investigated and it was identified that it affects quality and workability of equipment parts. Changes that occur in metal products structure during cold treatment by pressure, which lead to changes in physical and mechanical properties of products, have been analyzed. It was established that grains and borders between them, which determine internal structure of metal products, change their shape and size during cold rolling, depending on percentage reduction value. It is offered to consider grain borders as amorphous layer. Methodology has been developed to study influence of deformation degree during cold rolling to grain size of metal internal structure and intergranular layer volume. Intergranular surface area, its volume and part of surface volume from metal volume were determined. Parameters of internal structure of low-carbon steel were calculated depending on reduction value during cold rolling. According to study results, interconnection between grains size and deformation degree was established; and percentage reduction influence to grain size and borders between them was determined, obtaining a minimum standard grain size with percentage reduction of over 80 %; yield strength and its growth for metal alloy during cold rolling are established, which allows controlling the strength of steel by adjusting the grain size and their junction surface. It is shown that with an increase in deformation degree, yield strength of metal product material increases in hyperbolic dependence, and fraction of amorphous layer and strength properties of low-carbon steel change almost equally in exponential functions. It is revealed that during cold rolling, it is possible to control internal properties of obtained product by adjusting reduction value.

Evaluation of Heavy Metals in Catfish and Tilipia Fish from Bayelsa River Nigeria

The volume of heavy metals in two different fish samples were examined in this report, dry ashing was adopted to digest the samples and the determination of the heavy metals were evaluated using atomic absorption spectrophotometer. from the analyzed sample the concentration of cadimium in all the samples analyzed were below WHO permissible limits which is 0.2 mg/kg, From the different analyzed samples the concentration of lead was below the WHO’s allowable limits which is 0.05 mg/kg, however, catfish and tilapia fish samples gotten from Amasomma have the highest concentration of lead 0.0042 ±0.0021 and 0.0030 ±0.001 respectively. The concentration of cadmium, Aluminium and Manganese are below WHO permissible limits for these heavy metals.

Eddy Current Flow Meter Measurements in Liquid Sodium at High Temperatures

Abstract We present measurement results for the flow rate of liquid sodium at temperatures up to 700 °C that were obtained with a high-temperature prototype of an immersed eddy current flow meter. The experimental campaign was conducted at the SOLTEC-2 sodium loop at KIT. The main objective of the experiments is the high-temperature qualification of the Eddy Current Flow Meter as part of the safety instrumentation of generation IV liquid metal-cooled fast reactors. There it is intended to be used for monitoring the flow rate of the coolant and to detect possible blockages of subassemblies. Due to the large liquid metal volume, the sensor has to be located close to the subassemblies, therefore measurements from outside of the vessel are not possible and an immersed sensor is required. We demonstrate the successful application of the immersed eddy current flow meter (ECFM) at such high temperatures and identify the relevant effects with impact on the sensor performance.

The Effect of Core Metal Layer Thickness on the Behavior of Carall Under Low Velocity Impact Loading

Fiber metal laminates are the advanced composite materials, in which the metal and FRP layers are stacked alternatively to achieve the desired properties. The presence of FRP layers enhances the fatigue, fracture properties and weight savings. Durability and plasticity of the metal plays a significant role in the design of fiber metal laminates. This study evaluates the role of middle metal layer (core) thickness on the behavior of Carall fiber metal laminates under low velocity impact loading. Two types of Carall 3/2 with middle layer of varying thickness are considered. The metal volume fraction is same for both the laminates. Finite element simulations have been carried out for the laminates considered according to the standard ASTM D7136. Johnson–cook plasticity and damage model and two-dimensional Hashin damage criteria have been used to model the aluminum and CFRP respectively. From the study, it was found that the placement of thicker layer at the middle position in the Fiber metal laminate enhances the impact resistance of Carall. The energy absorption studies also indicate that the presence of thicker layer at the middle position increases the energy absorption capability.

Binder-Free CoMn2O4 Nanoflower Particles/Graphene/Carbon Nanotube Composite Film for a High-Performance Lithium-Ion Battery

Manganese-based bimetallic oxides show a high theoretical specific capacity, making them a potential next-generation lithium-ion battery anode material. However, as with metal oxide anode materials, aggregation, volume expansion, and poor conductivity are the main obstacles. In this manuscript, flexible CoMn2O4/graphene/carbon nanotube films were successfully prepared through a facile filtration strategy and a subsequent thermal treatment process. When used as anodes for lithium batteries, these films can be pressed onto nickel foam without other conductive additives and binders, which simplifies the manufacturing process. When used as an anode in the lithium-ion battery, CoMn2O4/GR/CNT film exhibits a high discharge capacity of 881 mAh g−1 after 55 cycles. This value is ~2 times higher than the discharge capacity of CoMn2O4. The three-dimensional GR/CNT carrier effectively dispersed CoMn2O4, preventing its aggregation and alleviating the problem of volume expansion.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ТОКАРНОЙ ОБРАБОТКИ ЖАРОПРОЧНЫХ СПЛАВОВ ВВЕДЕНИЕМ В ЗОНУ РЕЗАНИЯ ЭНЕРГИИ УЛЬТРАЗВУКОВОГО ПОЛЯ

The use of difficult-to-process heat-resistant alloys is widely used in the design of aircraft engines and gas pumping units. As a rule, thin-walled shell structures are made from them, providing a high density of the layout (for example, blades, electric unicycles). The peculiarity of the manufac-ture of such structures is a small (compared to the occupied volume of the entire product) volume of metal, in which the heat generated during shaping is distributed. Given the low thermal conductivity of such alloys (up to 4-5 times less compared to steels), the shaping of parts from them is associated with the risk of warping in combination with low productivity of blade processing with carbide tools. More effective, but little studied is the processing with tools made of mineral ceramics with the introduction of the energy of the ultrasonic field into the cutting zone. The purpose of the research is to develop a high-performance technology for pre-processing workpieces made of heat-resistant alloys with tools made of mineral ceramics, characterized by a minimum depth of defects in the surface layer.
 Methods. The research was carried out on machine tools in the manufacture of non-rigid parts of aircraft by turning blanks from the heat-resistant alloy HN45MVTYUBR with cutters made of mineral ceramics with the introduction of the energy of the ultrasonic field into the processing zone. 
 It has been established that the use of ultrasonic vibrations during pretreatment with mineral-ceramic tools without coolant can reduce the depth of the defective layer by up to one and a half times and increase productivity by up to 30 times.
 Taking into account the reduction in the depth of the defective layer, it becomes possible to reduce the allowances for final processing, and consequently, to reduce the duration of the technological process and the cost of manufacturing parts.

Modern Trends in Foundry

The production volume of metals and their alloys, taking into account the current demand for materials containing steel, cast iron, non-ferrous metals and their alloys, will continue to increase in the near future [...]

Temperature effects on thermodynamic properties of rare-earth ytterbium

Thermodynamic quantities (including Debye temperature and frequency, atomic mean-square displacement, specific heats at constant volume and constant pressure, linear thermal expansion coefficient, and total entropy) of face-centered cubic ytterbium metal have been studied by means of the statistical moment method in statistical mechanics. This theoretical approach allows us to calculate these thermodynamic quantities taking into account the anharmonicity of lattice vibrations. Numerical calculations for ytterbium have been conducted in temperature range from 0 K to 1100 K using Lennard-Jones potential to describe the interaction between ytterbium atoms. Our derived results are compared with those of mean-field potential approach as well as previous experimental data showing the good agreement. We have shown that the atomic mean-square displacement contains the zero-point vibration (quantum effect) at low temperature. At high temperature it changes linearly with respect to temperature. Furthermore, our theoretical calculations have also pointed out the anharmonic contribution to specific heat at constant volume of ytterbium metal is negative with temperature. This research presents an effective statistical approach to study temperature effects on thermodynamic quantities of materials.

The Experimental Study on the Mechanical Properties of Fiber-Reinforced Metal Laminates Using an Innovative Heat-Solid Integrated Forming Technology

In the forming process of fiber-reinforced metal laminates (FMLs) product, the exploratory compound forming technology, including hot stamping of aluminum alloy and laying process of fiber prepreg which is named HFQ-FMLs was proposed to solve the puzzles such as weak rigidity, low strength and integration deformation with large difficulty, and the feasibility and mechanical properties of the innovative forming process were studied. Firstly, based on the modified metal volume fraction formula, the theoretical values of the mechanical properties of the HFQ-FMLs plates were calculated. Compared with the experimental results, the minimum error is 1%, proving that the HFQ-FMLs technology scheme is feasible. Secondly, three kinds of metal sheets with different heat treatments and specimens by HFQ-FMLs were carried out for the tensile tests, the mechanical properties distributions were demonstrated, and the influence regularity of the strain rate and rolling direction on the stress analysis was considered at the same time. As can be seen from the distribution of yield strength and tensile strength, the yield stress of metal sheets obtained by HFQ-FMLs technology along the 45° is superior to the raw material and can increase by 46% under strain rate = 0.01 s−1. While, because the vacuum thermal curing treatment makes the aluminum alloy happen double aging, the metal sheet strength dropped, and the jointing strength between the metal and fiber prepreg became weak too, which made the strength limit of the new material improve weakly. Thirdly, the fractured style of the FMLs under different conditions was studied qualitatively. It is helpful to achieve the development rule of defects, optimize the craft route, and avoid deformation failure.

Differential Analysis and Prediction of Planar Shape at the Head and Tail Ends of Medium-Thickness Plate Rolling

This paper aims to improve planar shape prediction accuracy in the rolling process of medium and thick plates. We present a model based on the strip method that addresses limitations in predicting planar shape variations at the head and tail ends of rolled pieces. By analysing the rolling process, we introduce the concept of an imaginary strip longitudinal length difference to represent planar shape characteristics effectively. By analysing the change in metal shape in the rolling deformation zone, the calculation formula for metal volume in the deformation zone is derived. This establishes a relationship between the longitudinal length difference at the rolled piece ends and the metal volume in the deformation zone. The prediction of plane shape difference between the end and the head of medium and medium-thickness plate is realized. The experimental results confirm the feasibility and effectiveness of the proposed method.

Fatigue condition monitoring of notched thermoplastic-based hybrid fiber metal laminates using electrical resistance measurement and digital image correlation

In this work, the monitorability of fatigue damage in notched thermoplastic-based hybrid fiber metal laminate, containing AA6082-T4 sheets and glass and carbon fiber-reinforced polyamide 6, is investigated using constant amplitude tests. Electrical resistance measurement and digital image correlation were combined to determine the initiation and evolution process of fatigue damage. Preliminary to the application of the electrical resistance measurement during fatigue load, basic investigations regarding necessary measurement accuracy and conditions, e.g. temperature and cross-section influence, were conducted to achieve reliable measurement results. Via digital image correlation fatigue crack growth was determined and correlated with the change in electrical resistance for two metal/fiber-reinforced polymer layer configurations (2/1 and 3/2) and notch geometries (drilling hole and double-edge notch). The results show that reliable detection of fatigue-related damage states is possible independent of aluminum sheet treatment (mechanically blasted or anodized surface), with earlier crack initiation and faster propagation for higher metal volume fraction (layer configuration 2/1). For the two investigated notch geometries an overall similar crack behavior was found. The electrical resistance values directly correlate to varieties of crack formation and growth, representing the aluminum sheet damage progress of the laminate well, and enabling the possibility of e.g. a limit value-based failure criterion. However, geometry and crack-related changes in electric current flow and thus current density must be taken into account for targeted monitoring of the laminate condition, as they cause significant changes in electrical resistance.

Arbuscular mycorrhizas amplify the risk of heavy metal transfer to human food chain from fly ash ameliorated agricultural soils

Soil contaminants threaten global food security by posing threats to food safety through food chain pollution. Fly ash is a potential agent of soil contamination that contains heavy metals and hazardous pollutants. However, being rich in macro- and micronutrients that have direct beneficial effects on plant growth, fly ash has been recommended as a low-cost soil ameliorant in agriculture in countries of the Global South. Arbuscular mycorrhizal fungi (AMF), ubiquitous in agricultural soils, enhance efficiency of plant nutrient uptake from soils but can equally increase uptake of toxic pollutants from fly ash ameliorated soils to edible crop tissues. We investigated AMF-mediated amplification of nutrient and heavy metal uptake from fly ash amended soils to shoots, roots and grains of barley. We used a microcosm-based experiment to analyse the impacts of fly ash amendments to soil in concentrations of 0 (control), 15, 30 or 50% respectively, on root colonization by AMF Rhizophagus irregularis and AMF-mediated transfer of N, P and heavy metals: Ni, Co, Pb and Cr to barley tissues. These concentrations of fly ash are equivalent to 0, 137, 275 and 458 t ha−1 respectively, in soil. Root AMF colonization correlated negatively with fly ash concentration and was not detected at 50% fly ash amendment. Shoots, roots and grains of mycorrhizal barley grown with 15, 30 and 50% fly ash amendments had significantly higher concentrations of Ni, Co, Pb and Cr compared to the control and their respective non-mycorrhizal counterparts. Presence of heavy metals in barley plants grown with fly ash amended soil and their increased AMF-mediated translocation to edible grains may significantly enhance the volume of heavy metals entering the human food chain. We recommend careful assessment of manipulation of agricultural soils with fly ash as heavy metal accumulation in agricultural soils and human tissues may cause irreversible damage.

Correlation between toughness and metal volume fraction in carbon-glass fiber laminates tested under tensile loading

ABSTRACT The conducted work investigates the correlation between toughness characteristics and metal volume fraction in Fiber Metal Laminates (FMLs) subjected to tensile loads. Aerospace grade Al 7075-T6 was utilized as the varying metal alloy in the study. The metal alloy was combined with glass and carbon fiber layers to create different configurations of FMLs with varying stacking sequences. For better adhesion between metal and composite parts, aluminum layers were etched with sodium hydroxide and chromic-sulfuric acid solutions. The laminate sheets were prepared using the hand layup method which was followed by a vacuum bagging process. Specimens were cut and tested as per ASTM standard. Results of the experimentation showed that the aluminum volume fraction is directly related to the failure strain and modulus of toughness, however, inversely proportional to the stiffness characteristics of the laminates. The highest improvement of 111% in toughness parameter in comparison to pure composite laminate was reported. Finally, a comprehensive analysis on the type of fracture behavior in comparison to classical laminate theory was critically discussed.