High Material Utilization Research Articles

Self‐Lubricating Physical Vapor Deposition Coatings for Dry Cold Massive Forming

Cold massive forming, particularly forward extrusion of steel, is characterized by high material utilization, product quality, and resource efficiency. Currently, enormous quantities of mostly ecologically harmful lubricants are required, leading to the demand for lubricant‐free cold forming. Furthermore, cost savings are achievable due to shorter lead times. However, the requirements for the tools cannot be met without the application of wear‐resistant and friction‐reducing hard coatings. The self‐lubricating hard coatings (Cr,Al)N + Mo:S and (Cr,Al)N + W:S with attuned material design deposited by physical vapor deposition (PVD) offer high potential for the realization of dry cold forming of steel. The process chain for the comprehensive characterization of the developed coating systems comprises analyses of coating and compound properties as well as two different model tests to determine the tribological behavior. One of the used tribometers represents an open tribological system, which is particularly suitable for simulating the loads occurring during cold massive forming of steel. The analyses reveal that with Mo and S modified coatings exhibit higher potential for ecologically sustainable cold forming due to their better mechanical properties and compound properties between the coatings and the cold work steel substrate compared with W and S modified coatings.

Progressive microforming of pin-shaped plunger parts and the grain size effect on its forming quality

Progressive microforming of bulk microparts by directly using sheet metals has been developed to address the issues of preform/billet positioning, transportation and ejection in microforming, and it has potential to be used for making complex pin-shaped microparts with high productivity and material utilization. In this research, a progressive microforming system with blanking and extrusion operations to make two types of pin-shaped plunger parts by using brass sheets was developed, and the grain size effect was investigated from the aspects of deformation load, dimensional accuracy, microstructural evolution and surface quality. It is revealed that the grain size effect results in the deviation of punch stroke and the variation of part dimension. The formation and characteristics of shear band and dead metal zone are related to velocity gradient and strain accumulation. The forming defects including micro cracks, micro pits, uneven surface and longitudinal surface texture easily occur on the body and tail feature, and micro voids appear with the coarse-grained material. The circular surface, however, shows the desirable quality with each grain size. All these findings provide a basis for mass production of complex pin-shaped microparts by progressive microforming and enrich the knowledges from deformation behavior and product quality assurance aspects.

Fast and Reversible Four‐Electron Storage Enabled by Ethyl Viologen for Rechargeable Magnesium Batteries

AbstractMagnesium (Mg) batteries are the most promising “post‐lithium‐ion” energy storage technologies owing to their high theoretical energy density, low cost, and intrinsic safety with air and moisture. However, the development of Mg batteries has been limited to cathode materials leading to low power, low reversible energy density, and poor cycle life. Here, a new Mg cathode is reported based on ethyl viologen (EV), which not only has a fast redox couple EV2+/EV0 but also is capable of coupling with redox‐active anions, such as iodide (I−), achieving a total four‐electron storage. The EV2+/EV0 redox couple demonstrates a superior rate performance (10 C) and stable cycle life (500 cycles) owing to intrinsic fast electrode kinetics. A high material utilization (>80%) can be achieved at 1.0 C under a high areal loading of 5 mg cm−2. When coupling with iodide I−, a reversible four‐electron storage is achieved with a high energy density (304.2 Wh kg−1) and a stable cycle life (>100 cycles). This study provides effective strategies for designing reversible multielectron storage for high‐rate and high‐energy rechargeable Mg batteries.

Three-dimensional PdCuM (M = Ru, Rh, Ir) Trimetallic Alloy Nanosheets for Enhancing Methanol Oxidation Electrocatalysis.

Owing to their intrinsically high activity and rich active sites on the surface, noble metal materials with an ultrathin two-dimensional nanosheet structure are emerging as ideal catalysts for boosting fuel cell reactions. However, the realization of controllable synthesis of multimetallic Pd-based alloy ultrathin nanosheets (NSs) for achieving enhanced electrocatalysis evolved from compositional and structural advantages remains a grand challenge. Herein, we report a universal method for the construction of a new series of the three-dimensional (3D) multimetallic PdCuM (M = Ru, Rh, Ir) superstructures that consist of ultrathin alloy NSs. Different from the conventional 2D ultrathin nanostructure, the 3D PdCuM NSs that endowed with abundant routes for fast mass transport, high noble material utilization efficiency, and ligand effect from M to PdCu display large promotion in electrocatalytic performance for the methanol oxidation reaction. Impressively, the composition-optimized Pd59Cu33Ru8 NSs, Pd57Cu34Rh9 NSs, and Pd63Cu29Ir8 NSs show the mass activities of 1660.8, 1184.4, and 1554.8 mA mg-1 in alkaline media, which are 4.9, 3.5, and 4.6-fold larger than that of commercial Pd/C, respectively. More importantly, all of the PdCuM NSs are also very stable for long-term electrochemical tests.

31.5: Invited Paper: Solution Processable Materials for Printed OLED Displays

Ink‐jet printing is the most promising manufacture technology for large area OLED displays owning to its high materials utilization and low manufacturing cost. However, the performance of solution processed OLED devices (especially the life span) is still far below the evaporated ones, which is mainly due to the lack of high performance soluble OLED materials. The traditional strategies to increase solubility of organic functional molecules usually decrease their functionalities, such as emissive efficiency and device stability. Here we demonstrate a rational strategy to improve the stability of solution processed OLED devices by introducing novel organic emissive materials and optimization of the materials system in the emissive layer.

Tribological Property of Selective Laser Melting–Processed 316L Stainless Steel against Filled PEEK under Water Lubrication

As a 3D printing technology, selective laser melting has remarkable advantages such as high processing flexibility, high material utilization, and short production cycle. The applications of selective laser melting technology in industry have become quite extensive. There are many tribological studies on selective laser melting materials, but few based on water lubrication (Zhu, et al., Journal of Zhejiang University-Science A, 19(2), pp 95–110). In this article, the tribological properties of 316L stainless steel processed by selective laser melting and traditional methods have been studied under water lubrication. Polyether ether ketone (PEEK) filled with carbon fiber (CF)/polytetrafluoroethylene (PTFE)/graphite was selected as the counterpart. 316L stainless steel and PEEK are a tribopair commonly used in water hydraulics. This study is of great significance to the application of selective laser melting material of tribopairs in water hydraulics. Friction and wear tests were carried out on a pin-on-disc contact test apparatus under different operating conditions. The friction coefficient, specific wear coefficient, scanning electron microscopy (SEM) of the worn surface, and energy-dispersive spectroscopy (EDS) of the surface adhesions of the three tribopairs were measured and compared. The results revealed that the friction coefficient of the selective laser melting (SLM) 316L stainless steel was significantly higher than that of traditionally processed (TP) 316L stainless steel, which might be caused by the pores on the surface of SLM 316L stainless steel. Adhesion and cutting on the surface of SLM 316L stainless steel were also more serious, resulting in a higher specific wear coefficient of its counterpart PEEK composite compared to PEEK composite against TP 316L stainless steel.

Research on the Shunting Precision Forging of Ribbed Plate Gear Blank Based on DEFORM-3D Finite Element Analysis Under the Framework of New Engineering

In order to solve these problems in the precision forging, such as non-saturate, folding, high energy consumption and low material utilization, a certain type motor vehicle of ribbed plate gear blank was selected as the main focus. Based on the principle of shunting and the law of minimum damping, the finite element model of shunting precision forging was established by using finite element numerical simulation software DEFORM-3D, and the temperature field, equivalent strain field and workpiece were analyzed in depth. The results show that the end faces of ribbed plate are flat and there are no folding defects at the bottom. The influence of damage and forming load on forming process and quality provide theoretical basis and technical support for shortening R&D cycle and optimizing reasonable process parameters in actual production.

Characteristics, Industrial Application, and Prospects of Continuous Extrusion Technology

At present, continuous extrusion technology is applied in the industrial production of traditional non-ferrous metal profiles, composite profiles, and thin-walled hollow profiles, such as pipes, belts, wires and rows. This technology yields energy savings, high material utilization rates, automatic production, large manufacturing-product lengths, labor savings, and requires small floor space. The present paper introduces the characteristics of continuous extrusion technology and some industrial application examples, and focuses on the development prospects of multi-blank multi-round continuous extrusion technology.

Understanding the Effect of Interlayer on the Performance of All-Solid-State Li2s Batteries

Li−S batteries are considered a promising technology for next generation batteries, due to their high energy density and low cost of sulfur. The traditional liquid Li−S batteries, however, suffer from severe capacity fading and low Coulombic efficiency owing to processes occurring at the sulfur cathode. The electrochemical conversion reaction between S8 and Li2S involves a phase change where soluble lithium polysulfide intermediates are produced, causing so-called polysulfide shuttle phenomena. In order to mitigate the issues related to polysulfides, various approaches such as physical confinement of polysulfides or fabricating protective layer on Li anode were employed. However, the shuttle reaction still remains, affecting the cycling performance of the battery. One promising approach to proceed the Li−S battery chemistry without producing polysulfide intermediates is to utilize non-solvating electrolyte such as inorganic solid electrolytes (SE). The use of solid electrolyte eliminates the possibility of polysulfide dissolution, improving the energy efficiency of Li−S batteries. In addition, sulfide solid electrolyte such as Li7P­3S­11­ exhibits an ionic conductivity of ~10-3 S cm-1 comparable to that of the conventional 1 M ethereal electrolytes. Despite these advantages, the performance of all-solid-state Li−S battery (ASSLSB) incorporating inorganic solid electrolyte is much worse than Li−S cells with liquid electrolytes in terms of active material utilization and rate capability. The biggest challenge lies in constructing sufficient Li+ ion transport channel within the composite cathode, since SEs do not infiltrate into cathodes as liquid electrolytes. There have been considerable research efforts to improve the ionic conductivity of the cathode, such as ball-milling S8 (or Li2S), conductive carbon, and SE to prepare the composite cathode. However, only limited improvement was achieved on increasing active material utilization by simply ball-milling the three components. This is likely due to the poor physical contact between SE and cathode active material, leaving the active material electrochemically inactive (Figure 1a). In an effort to improve the interfacial contact and increase the capacity, we report a strategy of using an interlayer between the electrode/electrolyte interfaces (Figure 1b). Our solid-state cell with interlayers exhibits much higher capacity compared to that of bare sample without interlayers, achieving ~80% active material utilization at cycle 60 with dramatically reduced impedance relative to the bare cell. The interlayer in ASSLSB infiltrates into void space in composite cathode creating contact between the active material and SE resulting in high active material utilization. This increased contact leads to smaller cell impedance due to the decreased interfacial resistance. Additionally, the interlayer provides buffer space for volume contraction and expansion during electrochemical cycling, thereby preventing the physical delamination of cathode components. Figure 1

Precision forming of long-axis forgings with rib-web sections via billet optimization based on flow characteristics

During the forming process, the flow characteristics of materials are crucial for obtaining qualified precise products. In the forging process of long-axis forgings with rib-web sections, the material in the section would be split and extruded to both sides. It could be easy to cause incomplete forming or excessive flash scrap by using the traditional center-coincidence rule to design billet. In present work, the material flow law and its influencing factors during forging the rib-web section were analyzed aiming to develop a better billet design method for obtaining high material utilization ratio and avoiding multiple trials and errors of finite element numerical simulation. Based on the stress analysis of material flow by slab method, a calculation model of splitting-flow was established to determine the location of the splitting line in each forming step. Furthermore, the material volume distribution model in the whole forming process was established through the step-by-step accumulation of the splitting-flow material volume. By iteratively changing the billet position and calculating the volume distribution, the center positions of the billet sections can be optimized to ensure that both sides of the section are simultaneously filled, which results in high material utilization ratio up to 98%. The effectiveness of the new billet design method was verified by forming a knuckle control arm.

A NiCo2S4 /hierarchical porous carbon for high performance asymmetrical supercapacitor

A NiCo2S4 nanoparticles composite, in-situ grown on rice husk hierarchical porous carbon, is synthesized through a facile one-step hydrothermal method for energy storage. The NiCo2S4 nanoparticles with a size of 20 ± 10 nm are homogeneously distributed on the carbon matrix, leading to a high material utilization and high capacity, significantly outperformed the pure NiCo2S4. The chemical bonds of C-O-Co and C-O-Ni between the NiCo2S4 nanoparticles and the carbon matrix not only result in a superior power density, but also improve the cycling stability. An asymmetrical supercapacitor is assembled using the composite material and commercial YP-50 activated carbon and shows high energy density, high power density and excellent cycling stability. The hydrothermal method can be extended to synthesize other composite materials for energy storage devices.

In Situ Generated Li2S-C Nanocomposite for High-Capacity and Long-Life All-Solid-State Lithium Sulfur Batteries with Ultrahigh Areal Mass Loading.

All-solid-state lithium-sulfur batteries (ASSLSBs) have attracted great attention due to their inherent ability to eliminate the two critical issues (polysulfide shuttle effect and safety) of traditional liquid electrolyte based Li-S batteries. However, it remains a huge challenge for ASSLSBs to achieve high areal active mass loading and high active material utilization simultaneously due to the insulating nature of sulfur and Li2S, and the large volume change during cycling. Herein, a Li2S@C nanocomposite with Li2S nanocrystals uniformly embedded in conductive carbon matrix, is in situ generated by the combustion of lithium metal with CS2. Benefiting from its unique architecture, the Li2S@C exhibits exceptional electrochemical performance as cathode for ASSLSBs, with both ultrahigh areal Li2S loading (7 mg cm-2) and 91% of Li2S utilization (corresponding to a reversible capacity of 1067 mAh g-1). Moreover, the Li2S@C also possesses outstanding rate capability and cycling stability. High reversible capacity of 644 mAh g-1 is delivered at 2 mA cm-2 even after 700 cycles. This work demonstrates that ASSLSBs with superior electrochemical performance can be realized via rational design of the cathode structure, which provides a promising prospect to the development of ASSLSBs with practical energy density surpassing that of lithium ion batteries.

Overview of 2-Degree-of-Freedom Rotary-Linear Motors Focusing on Coupling Effect

The 2-degree-of-freedom (2DoF) rotary–linear (RL) motors are capable of implementing pure rotary motion, pure linear motion, or helical motion along the same axis, which have definite advantages of integrated structures, high material utilization, and fast response. Therefore, such motors have an extensive application prosperity ranging from robots, electric vessels, electric and hybrid vehicles, screwing machines, drilling machines, and intelligent machining systems. In this paper, an overview of 2DoF RL motors is presented, which can be divided into the motors with crossed RL magnetic field and those with independent RL magnetic fields. The development of various topologies and the corresponding coupling effect, optimization designs, and decoupling control algorithms are discussed and reviewed.

A multifunctional luminescent network film electrochemically deposited from a new AIEE emitter for OLEDs and explosive detection

Abstract Electrochemical polymerization (EP) has attracted considerable attention because of its high material utilization, simple process and low cost. In this work, a new AIEE-active blue-emitting molecule, TCzDPAn, was synthesized. The multifunctional luminescent network film, with TCzDPAn as the building block, was conveniently prepared by EP. The EP film exhibits smooth surface morphology and high thermal stability, which shows great potential as light-emitting materials. In addition, the EP film shows very sensitive detection for 2,4,6-trinitrophenol (TNP) in solution and vapor states, through the synergetic effect of photo-induced electron transfer(PET) and fluorescence resonance energy transfer (FRET). Overall, the study indicates the potential of the multifunctional EP film as OLEDs materials and fluorescent sensors, which is attributed to the specific molecular features of TCzDPAn and the intrinsic properties of the EP film.

Microstructure and mechanical properties of wire arc additively manufactured AZ80M magnesium alloy

Wire arc additive manufacturing (WAAM) with high deposition efficiencies and material utilization rate was carried out by using AZ80M magnesium alloy in this work. The microstructure and mechanical properties of the WAAM AZ80M were tested and studied. The results showed that the WAAM AZ80M was mainly composed of α-Mg, β-Mg17Al12 and Al2Y phases and had obvious inhomogeneous characteristics along the deposition direction. Because of the microstructure inhomogeneity and micro defects in the interlayer region of the WAAM AZ80M, its average tensile strength at the horizontal and vertical directions was different with the values of 308.7 MPa and 237.3 MPa, respectively.

Experimental study on asynchronous construction for composite bridges with corrugated steel webs

Asynchronous construction is a new construction method for composite girder bridges with corrugated steel webs. This new construction technology has multiple advantages over conventional cantilever construction technology, including a simple basket structure, low steel consumption, high material utilization, short construction period and superior stability. Herein, a 1:1 full-scale corrugated steel web model test is designed based on the Fenghua River Bridge, which is the longest span composite girder bridge with corrugated steel webs in China. This test analyzes the shear stress distribution of corrugated steel webs under the most unfavorable stress conditions and the ultimate bearing capacity of single corrugated steel webs under the most unfavorable load conditions during asynchronous construction. The deformation and stress conditions are measured to identify critical stress areas during construction. Additionally, the safety of each area during construction is verified to provide guidance for asynchronous construction plans for the same type of bridge structures.

Characteristics Analysis of the Motions of the Two-Degree-of-Freedom Direct Drive Induction Motor

The 2-degree-of-freedom direct drive induction motor (2DoFDDIM) is capable of implementing rotary linear or helical motion, which has the definite advantages of integrated structure, high material utilization, and so on. In this paper, the characteristics analysis of the three kinds of motions is presented. The air-gap magnetic field distributions and mechanical characteristics of the 2DoFDDIM with three motions are derived respectively. The results show that there is super synchronous speed or velocity phenomenon for rotary or linear motion. Moreover, the coupling effects between the rotating and travelling wave magnetic fields and that between the two mechanical motions will deteriorate the performance of the three-dimensional (3-D) helical motion compared with the two-dimensional (2-D) motion (rotary or linear). The expressions of the resistant torque and force caused by the coupling effect are derived, which are verified by 3-D finite-element models (FEMs). The results regarding the weakening of the output torque of helical motion and interacting magnetic field obtained from FEMs are then verified by experimental tests. Finally, the skewed slot method is applied to 2DoFDDIM, which successfully improves the performance of helical motion aiming to compensate the coupling resistant torque and force.

Inkjet printed perovskite solar cells: progress and prospects

In the field of photovoltaic materials, perovskite has attracted extensive attention during the past years, owing to its excellent photovoltaic properties, including high charge carrier mobility, low exciton binding energy, long charge carrier diffusion length, broad light absorption spectrum, large absorption coefficient, and low-cost solution processability. However, due to the limitations of film preparation methods (typical spin coating), industrial large-scale production of perovskite solar cells is still in infancy. The inkjet printing technology is a significant manufacturing technology developed from home and office printing and widely used in various printing electronics industries. Compared with other deposition methods, it possesses many advantages, including low cost, high material utilization, high patterning precision, etc. As a direct writing technology, the inkjet printing has shown great industrial potential and is expected to be employed in the industrialization of perovskite solar cells. In this paper, we review the research progress of perovskite solar cells fabricated via the inkjet printing and the application of inkjet printing technology to various functional layers (electrode, hole transport layer, electron transport layer, perovskite active layer). Finally, the challenges of inkjet printed perovskite solar cells at this stage are discussed, and the commercialization direction of inkjet printed perovskite solar cells is also pointed out.

Experimental Study on Bearing Capacity of Reinforced Steel Tubular Scaffold under Uniform Loads

Five groups of tests were designed to analyze the influence of node types (fastener connection and mortise‐and‐tenon joint) and reinforcement modes of top horizontal cross rods (weak truss and stiffening truss) on the bearing capacity of the steel tubular scaffold under vertical uniform loads. Loading phenomenon, bearing capacity, failure mode, displacement at key positions, and strain development characteristics during tests were analyzed. The following conclusions were drawn: (1) The fastener scaffold reinforced by a top truss showed the highest bearing capacity and high material utilization. (2) The fastener scaffold reinforced by a top weak truss increased the bearing capacity and caused coordinated deformation of the top horizontal force rods. (3) The node displacement of the mortise‐and‐tenon scaffold was smaller than that of the fastener joint, whereas its bearing capacity was higher. (4) Vertical diagonal bracing can slightly increase the bearing capacity of the mortise‐and‐tenon scaffold but can also constrain the deformation of the vertical rods and change the failure mode.

A novel two-stage hybrid processing technique towards industrial manufacturing of the Cu(In,Ga)(S,Se)2 solar cell with materially efficient fabrication

The hybrid two-stage processing technique achieved the highly efficient CIGSSe solar cell with high material-utilization and a simple process for commercialization.