Metallic Binder Research Articles

EFFECT OF SINTERING TEMPERATURE TO MICROSTRUCTURE IN METAL BINDER JETTING

Metal Binder Jetting emerged and it has been developing an additive manufacturing method. Binder type, binder ratio, sintering process, and atmosphere couldn’t be transparently determined due to its development stage. In this study, effect of sintering temperature was investigated parts’ microstructure which manufactured by Binder Jetting Metal Additive Manufacturing. In manufacturing, SS316L metal powder used as a raw material, ultraviolet light cured and solid+fluid catalyzed cured resins used as binder. For solid+liquid catalyzed cured resin, furfuryl alcohol was selected as liquid binder, para toluene sulfonic acid was selected as solid catalyst. Isopropyl alcohol was used to dilute the ultraviolet light cured resin. The composition ratios and electron diffraction patterns of the samples were analyzed using optical and scanning electron microscopy.

Naringin administration mitigates oxidative stress, anemia, and hypertension in lead acetate-induced cardio-renal dysfunction in cockerel chicks.

Lead is one of the major pollutants that is harmful to both animals and humans. It is found in every aspect of the environment such as the air, water, and soil. This pollutant affects both wild and domestic birds. Naringin has an active principle called flavonoid that has been found to have medicinal properties, mostly because of its antioxidant and metal chelating properties. This study was carried out to investigate the protective effect of naringin as an antioxidant against lead-induced anemia, cardio and nephrotoxicity, and hypertension. This study also aimed at elucidating the use of naringin as a heavy metal binder in poultry feed. Thirty-six cockerel chicks were used for this study, and randomly grouped into six groups per group; group A served as the control, group B received Pb-only (300ppm), group C (Pb and naringin; 80mg/kg), group D (Pb and naringin; 160mg/kg), group E (naringin 80mg/kg), and group F (naringin 160mg/kg), respectively, for 8weeks. Lead (Pb) was administered via drinking water, while naringin was administered via oral gavage. Lead acetate intoxication precipitated anemia as indicated by significant reductions in the values of PCV, RBC, and Hb concentration in lead-treated chicks when compared with the controls. Also, lead administration induced hypertension together with increased oxidative stress, depletion of the antioxidant defense system, reduced nitric oxide production, and an increase in high blood pressure. Immunohistochemistry indicated high expressions of cardiac troponin, renal angiotensin-converting enzymes, and renal neutrophil gelatinase-associated lipocalin. Treatment with naringin corrected anemia, reduced oxidative stress, improved antioxidant system, reduced high blood pressure, and offered protection against lead acetate-induced cardio-renal dysfunction in cockerel chicks. We recommend that naringin should be incorporated poultry feeds as a metal binder.

Temperature dependent properties of Co-W-C alloys

Integrated Computational Materials Engineering (ICME) supports materials engineering by linking materials models at multiple length scales. Effective use of the ICME approach requires underlying data to fully enable a combination of appropriate models and software tools. In the Hardmetal world where materials are composites of hard carbides/nitrides with tough metal binders this requirement has many facets. This paper addresses one of these facets - the issue of the mechanical behaviour of typical Co based binder phases over a range of temperatures. Three Co-W-C alloys were manufactured to provide samples that could be tested at different temperatures and under various mechanical conditions. The principle of miniaturised testing was adopted to help generate as much information as possible from a restricted amount of original alloy. An important aspect was the phase content of the alloys since Co alloys can be FCC, HCP or HCP/FCC mixtures and resistivity measurements as a function of temperature were used to interpret the phase contents. Below the FCC/HCP phase transformation temperature the microstructure can be a mixture of HCP/FCC, dependent on composition and whether applied heating is increasing or decreasing (hysteresis in phase transformation kinetics). To fully characterise all these parameters and their effect on mechanical properties at different rates would be a significant effort in material manufacture, sample characterisation and testing resources. Consequently, an attempt was made to conserve resources by exploring these issues by completing multiple tests on a few samples of each of the three alloys, while in both the heating and cooling regimes.

Optimal Dressing of Diamond Abrasive Wheels with Metallic Binder

Optimal Dressing of Diamond Abrasive Wheels with Metallic Binder

Magnetic Properties and Microstructure of Ce-Cu-Al Low Melting Alloy Bonding Sm2Fe17N3 Magnet Fabricated by the Hot-Pressing Method

Sm2Fe17N3 compounds, having excellent intrinsic magnetic properties, are prone to decomposition at high temperatures; thus, a low melting point metal binder is the key to prepare high performance bulk magnets at low temperatures. In this paper, a new low melting point alloy Ce72Cu28-xAlx was used as the binders, and high-performance Ce-based alloy bonding Sm2Fe17N3 magnets were realized by the hot-pressing method. The experimental results demonstrated that the content of Al in the Ce-based alloys had an important influence on the performance of the magnets. High performance Sm-Fe-N bonded magnets with remanence of 10.19 KGs and maximum magnetic energy product of 21.06 MGOe were achieved by using 5 wt.% Ce72Cu22Al6 alloy as a binder. At the same time, it was found that the Ce72Cu28-xAlx alloy has a lower density and better bonding effect than the common Zn binder. Its bonding magnets still have higher performance even with extremely high oxygen content. Therefore, Ce72Cu28-xAlx alloy with low melting point is a promising new rare earth-based alloy binder. If the oxygen content of the alloy powders could be reduced, higher performance Sm2Fe17N3 bonded magnets can be prepared.

High energy density flexible and ecofriendly lithium-ion smart battery

The rapidly growing battery market demands both high energy density and waste-management solutions for the anticipated global annual battery waste of about two million metric tons. To address the energy-environment dilemma, we developed self-standing composite electrodes for Li-ion batteries without electrochemically inactive metal current collectors, additives, and binders, increasing energy density by up to 40%. The electrodes were prepared via in situ mixing of as-grown single-wall carbon nanotubes (SWNTs) with aerosolized electrode active materials, leading to adequate electrical conductivity and mechanical robustness. The SWNT scaffold exhibits a piezoresistive effect, with resistance depending on the voltage-weighted number of inter-nanotube contacts. We exploit this intrinsic piezoresistance of SWNT network for operando self-monitoring of battery structural health. The proposed solution-free battery fabrication technology and architecture eliminates environmentally harmful components and enables recycling by simple mechanical separation, aiming at safety and circular economy.

Compensation of sintering deformation for components manufactured by metal binder jetting using numerical simulations

PurposeThis study aims at compensating for sintering deformation of components manufactured by metal binder jetting (MBJ) technology.Design/methodology/approachIn the present research, numerical simulations are used to predict sintering deformation. Subsequently, an algorithm is developed to counteract the deformations, and the compensated deformations are morphed into a CAD model for printing. Several test cases are designed, compensated and manufactured to evaluate the accuracy of the compensation calculations. A consistent accuracy measurement method is developed for both green and sintered parts. The final sintered parts are compared with the desired final shape, and the accuracy of the model is discussed. Furthermore, the effect of initial assumptions in the calculations, including green part densities, and green part dimensions on the final dimensional accuracy are studied.FindingsThe proposed computational framework can compensate for the sintering deformations with acceptable accuracy, especially in the directions, for which the used material model has been calibrated. The precise assumption of green part density values is important for the accuracy of compensation calculations. For achieving tighter dimensional accuracy, green part dimensions should be incorporated into the computational framework.Originality/valueSeveral studies have already predicted sintering deformations using numerical methods for MBJ parts. However, very little research has been dedicated to the compensation of sintering deformations with numerical simulations, and to the best of the best of the authors' knowledge, no previous work has studied the effect of green part properties on dimensional accuracy of compensation calculations. This paper introduces a method to omit or minimize the trial-and-error experiments and leads to the manufacturing of dimensionally accurate geometries.

A versatile SPH modeling framework for coupled microfluid-powder dynamics in additive manufacturing: binder jetting, material jetting, directed energy deposition and powder bed fusion

Many additive manufacturing (AM) technologies rely on powder feedstock, which is fused to form the final part either by melting or by chemical binding with subsequent sintering. In both cases, process stability and resulting part quality depend on dynamic interactions between powder particles and a fluid phase, i.e., molten metal or liquid binder. The present work proposes a versatile computational modeling framework for simulating such coupled microfluid-powder dynamics problems involving thermo-capillary flow and reversible phase transitions. In particular, a liquid and a gas phase are interacting with a solid phase that consists of a substrate and mobile powder particles while simultaneously considering temperature-dependent surface tension and wetting effects. In case of laser–metal interactions, the effect of rapid evaporation is incorporated through additional mechanical and thermal interface fluxes. All phase domains are spatially discretized using smoothed particle hydrodynamics. The method’s Lagrangian nature is beneficial in the context of dynamically changing interface topologies due to phase transitions and coupled microfluid-powder dynamics. Special care is taken in the formulation of phase transitions, which is crucial for the robustness of the computational scheme. While the underlying model equations are of a very general nature, the proposed framework is especially suitable for the mesoscale modeling of various AM processes. To this end, the generality and robustness of the computational modeling framework is demonstrated by several application-motivated examples representing the specific AM processes binder jetting, material jetting, directed energy deposition, and powder bed fusion. Among others, it is shown how the dynamic impact of droplets in binder jetting or the evaporation-induced recoil pressure in powder bed fusion leads to powder motion, distortion of the powder packing structure, and powder particle ejection.

Deposition mechanisms and characteristics of nano-modified multimodal Cr3C2–NiCr coatings sprayed by HVOF

Abstract Nano-modified multimodal and conventional Cr3C2–NiCr coatings were fabricated by high-velocity oxygen-fuel spraying deposited on CuCrZr substrates. Results showed that individual nano-modified multimodal Cr3C2–NiCr particles were composed of nano (25−180 nm), submicron (200 nm to 0.5 μm), and micron (2–4.5 μm) Cr3C2 grains, NiCr binder phases, and a tiny amount of rare earth oxide additives. The nano-modified multimodal Cr3C2–NiCr coatings maintained a unique structure: submicron Cr3C2 grains embedded in the voids formed by micron Cr3C2 grains, NiCr binder phases and nano Cr3C2 grains imbedded in the voids formed by submicron and micron Cr3C2 grains, and nano Cr3C2 grains are dispersed in NiCr metal binder phases. A few discontinuous elongated amorphous and nanocrystalline phases existed in them. The mechanical interlocking was the dominant bonding mechanism accompanied by local metallurgical bonds. Compared to the conventional coating, the multimodal coating was uniform and dense (porosity was 0.3 ± 0.12%) as well as not obvious lamellar structures, the adhesive strength was 75.32 ± 1.21 MPa, exhibiting a 65 pct increase, and the microhardness was increased by about 18%. The lower porosity and higher strength of nano-modified multimodal structure coating were mainly related to dispersion distribution and synergistic coupling effects of Cr3C2 hard grains with different scales.

Distinguishing contributions of metal binder and ceramic phase to mechanical performance of cermets at different temperatures

It is crucial to clarify the effects of the ceramic phase, the metal binder, and temperature on the mechanical properties of WC-Co cermets, as a typical representative of cermet materials, due to highly demanded excellent high-temperature properties under harsh service conditions. Based on uniaxial compression tests and detailed microstructural characterization, this study quantified the deformation characteristics of the ceramic phase and the metal binder at room temperature and high temperatures applying multiple analysis methods. It distinguished different contributions of the ceramic phase and metal binder to the plasticity of the cermets during deformation, and proposed the mechanisms for the plastic deformation of cermets. The results indicated that the dislocation plasticity is the dominant deformation mechanism of the cermets, and the ceramic matrix is mainly responsible for the fracture strength and contributes significantly to the plasticity of the cermets both at room temperature and high temperatures. At high temperatures, grain boundary slip and phase boundary sliding also contribute to the plastic deformation of cermets.

Fracture behaviors of Ti(C, N)-based cermets with different contents of metal binder

Ti(C0.7,N0.3)-Mo2C–Ni cermets are fabricated by powder metallurgy methods. We systematically investigate the microstructure, fracture morphology, crack propagation mechanism, and interface characteristics of Ti(C, N)-based cermets with different Ni binder contents.The increased dissolution of carbides and carbonitrides leads to a large amount of (Mo,Ti)(C,N) solid solution precipitates, which then spontaneously nucleate, resulting in a significant increase in the content of white core-gray rim grains in the cermets with a high binder content. The increased Ni binder largely improves the flexural strength and fracture toughness of the Ti(C,N)-based cermets because of the ductile dispersion toughening. The rim-core interfaces have a superior atomic coherent relationship in all Ti(C,N)-based cermets owing to the small lattice mismatch. The lattice mismatch of the interface between the rim phase and metal binder is remarkably decreased with the increase in the binder content to construct an atomic coherent relationship. Thus, the increased Ni binder promotes atomic ordering at the interface between the ceramic grains and binder and strengthens the grain boundary. The characteristic (111) peak of nickel shifts to a larger angle due to the reduction in the Ni-based solid solution lattice distortion. Therefore, the effect of solid solution strengthening is diminished with the increase in binder content, which results in a decreased binder strength. In the Ti(C,N)-based cermets with low metal binder contents, the fracture of the grain boundary between the ceramic grains and binder is the predominant failure mechanism. The intergranular crack accompanied by crack branching is the main characteristic of crack propagation. A hybrid fracture mode of intergranular and transgranular cracks is observed in the Ti(C,N)-based cermets with a moderate binder content. As the binder content further increases, the plastic yield deformation and subsequent tearing of the metal binder are the main fracture characteristics because of grain boundary strengthening and decreased strength of the binder.

The Future for Room‐Temperature Sodium–Sulfur Batteries: From Persisting Issues to Promising Solutions and Practical Applications

AbstractRoom‐temperature sodium–sulfur (RT‐Na/S) batteries are emerging as promising candidates for stationary energy‐storage systems, due to their high energy density, resource abundance, and environmental benignity. A better understanding of RT‐Na/S batteries in the view of the whole battery components is of essential importance for fundamental research and practical applications. In particular, the components other than sulfur cathodes in preventing the migration of polysulfides and accelerating the reaction kinetics have been greatly overlooked. Such a biased research trend is also adverse to the broader applications for RT‐Na/S batteries, which have long been ignored in previous reviews. Herein, approaches to the historical progress toward practical RT‐Na/S batteries through a “teamwork” perspective are comprehensively summarized, and balanced research trends are encouraged to enable practical RT‐Na/S batteries. In the meantime, the persisting issues, promising solutions, and practical applications of advanced sulfur host design, Na metal anode protection, electrolyte optimization, separator modification, and binder engineering are clearly emphasized. Finally, the device‐scale evaluation in practical parameters and advanced characterization tools are thoroughly provided. This review aims to provide the “teamwork” perspective on the whole‐cell design and fundamental guidelines that can shed light on research directions for practical RT‐Na/S batteries.

Novel cermets based on vanadium oxycarbide with Co and Fe binders

This paper shows the ability of vanadium oxycarbide to form a hard phase within metallic binder (VCxOy-Co and VCxOy-Fe cermets) in a wide range of compositions (x = 0.1–0.9 and y = 0.2–0.5). Pellets of VCxOy-Co were densified during heating to 1450 °C and VCxOy-Fe to 1485 °C under argon flow without dwell. Obtained microstructures represented 3–11 μm grains of VCxOy surrounded by 12–18 vol% of binder, with relative density of 71–94% for VCxOy-Co and 84–96% for VCxOy-Fe, and having the average hardness of 10–13 GPa. Although the samples with more oxygen than carbon had smaller ceramic grains, too little carbon resulted in secondary phase. Higher carbon content provided the ordered V8C7 and V6C5 phases that made sintered cermets significantly harder in spite of residual porosity. Overall, iron-containing samples had a stronger ceramic-metal interface than cobalt samples based on fracture behavior.

Characterization of the elastic modulus of ceramic–metal composites with physical and mechanical properties by ultrasonic technique

Abstract The scope of this study, that is, the effect of the elastic modulus obtained by ultrasonic method on the physical and mechanical properties of tungsten carbide (WC)-based ceramic–metal composites, which have Ni and Co metallic binder composition produced by powder metallurgy and represented by high strength and hardness criteria, was investigated. In order to obtain composite samples in the study, it was sintered in a microwave furnace at different temperatures to combine the powder particles prepared at the rate of 60% Ni, 20% Co, and 20% WC by weight. Then, the velocities and longitudinal attenuation values of longitudinal and shear ultrasonic waves along the composite sample were measured using the ultrasonic pulse-echo method. The elastic modulus of the composites was determined using ultrasonic velocities and sample density. Hardness testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were also performed. The results show that the elastic modulus increases with the increase in sintering temperature and ultrasonic wave speeds, but decreases with the longitudinal attenuation value, considering the SEM images and XRD analysis. There is also a linear relationship between elastic modulus and stiffness.

(Invited) High Energy Density and Ecofriendly Lithium-Ion Battery with Operando Monitoring

In addition to recent worldwide renewable energy commitments, advances in electrical vehicle technologies, flexible electronics, smart wearable devices, and internet of things, have contributed to the increasing demand for batteries with a wide range of electrochemical and electromechanical properties. In response, the battery industry has launched intensive research and development efforts in search for new materials, technologies, and concepts. However, these rapid developments give rise to a growing concern on the impact of this industry on Nature. Hence, the rapidly growing battery market demands resolutions for both energy and waste-management challenges in anticipation of about two million metric tons of annual battery waste generated globally. One way to resolve this energy and environment dilemma is by revising the conventional battery architecture to assure both high energy density and efficient recyclability aiming at circular economy. Within this strategy we fabricated self-standing composite electrodes that eliminated electrochemically inactive metal current collectors and binders from the Li-ion battery architecture, increasing energy density up to 40%. These electrodes were prepared via in situ mixing of as-grown single-wall carbon nanotubes (SWNTs) with aerosolized electrode active materials in ratios (≥0.25 wt%) that provide adequate electrical conductivity and mechanical robustness under stretching (≤15%), bending (d≥2 mm) and twisting (θ~180o) cycles. Remarkably, the resultant SWNT scaffold in composite electrodes operates as an intrinsic piezoresistive strain sensor (Gauge Factor ~6.2) that for the first time allows in situ/operando self-monitoring of battery structural health without interfering with electrochemical reactions. Moreover, the developed solution-free fabrication method eliminates hazardous, toxic, and environmentally harmful components and procedures from the electrode production line and allows their recycling by simple sonication and recovering of the active materials. In addition, the absence of current collector foils and binder allows for easy recycling and recovery of the constituent materials by using physical separation methods. These new features not only reduce consumption of the natural resources but also promote the eco-friendly circular economy for batteries.

Corrosion Performance of Additively Manufactured Stainless Steel by Binder Jetting

The influence of microstructural defects on the corrosion resistance of AISI 316L additively manufactured with Metal Binder Jetting in high Cl- environments were studied herein. A comprehensive metallographic examination was conducted to identify microstructural defects followed by a corrosion study with electrochemical techniques with the aim of finding correlations between impurities in the microstructure and preferential nucleation sites. Despite, the high number of inclusions in the microstructure of the studied samples, none of the conducted corrosion tests showed a clear indication that they resulted in a decreased corrosion resistance as compared to areas with few inclusions. However, a significant higher pitting potential was observed on the as-printed samples compared to samples grinded with 600 grit SiC paper which will be discussed further.

Fe-based sintered matrix for diamond tools: microstructure, mechanical performance and crack initiation and propagation characteristics

To design Fe-Cu-Sn-Ni metal binders for diamond tools and optimize the performance of binders, Fe-based binders were prepared by hot-press sintering method using Fe powder, Cu powder, Sn powder and Ni powder as the raw materials. The phase constitution, microstructure, mechanical properties and crack formation were evaluated. Results showed that Fe-based matrixes are composed of Cu3Sn intermetallic compounds and several solid solutions, such as α-Fe, γ(Fe,Ni), and Cu13.7Sn. The relative high Sn content can increase the hardness of the sintered bulk samples and significantly reduce the bending strength. With the increase of Ni content, the hardness increases gradually, while the bending strength increases firstly and then decreases. The cracks initiate from brittle Cu3Sn intermetallic phases and quickly propagate in the brittle phases or along the interface between Cu3Sn intermetallic compounds and γ(Fe,Ni) phases. The propagation of crack can be impeded by Cu13.7Sn solid solution.

Tribological behaviour of different formulations of WC composites

WC-based composites are extremely resistant to wear and corrosion; they are used in numerous mechanical applications (e.g., pumps, valves, mechanical seals, flow control technology, etc.). They are generally produced by sintering tungsten carbide with a metal binder (cobalt is the most common). However, Co is part of the 2017 list of 27 critical raw materials with a high supply-risk and economic importance to which reliable and unhindered access is a concern for European industry and value chains. This paper aims at the mechanical and tribological characterization, by reciprocating sliding wear experiments and scratch tests, of new and innovative cemented carbide grades that contribute to the reduction/substitution of critical materials like the Co binder. It was found that Co plays an important role in the wear behaviour of hardmetals. On the other hand, the composites developed present wear rates close (although higher) to WC-Co, constituting valid alternatives for wear parts.

Using explosion loading to obtain coatings of chromium carbide and titanium mixtures in deposition mode

The paper presents the results of studies into the microstructure, chemical and phase composition of coatings deposited on a steel substrate using the sliding explosive loading of Cr3C2 chromium carbide and titanium powder mixtures. The equilibrium phase composition of coatings was calculated by computational thermodynamic modeling using the Thermo-Calc software package. The structure and elemental composition were studied using a FEI Versa 3D scanning electron microscope with an integrated EDAX Apollo X system for energy dispersive X-ray microprobe analysis. A Bruker D8 Advance diffractometer was used for X-ray phase analysis. It was shown that when the powder layer is loaded by a sliding detonation wave, it can be shifted along the substrate surface due to the horizontal mass velocity component of compacted material particles. This shift causes the inner layer of the compacted powder and the surface layer of the substrate to melt as a result of friction. The presence of a liquid phase prevents the compacted powder layer deceleration so that the major part of it is removed from the substrate surface. The liquid phase remaining on the surface undergoes rapid quenching due to heat removal into the substrate and forms a deposited coating containing both the components of the initial powder mixture and the components of the substrate to be coated. It was established that the deposited layer structure features by extremely high dispersion (grain size does not exceed 250 nm), and its phase composition turns out to be close to a thermodynamically equilibrium one. When using powder mixtures of chromium carbide with 40% titanium, a coating is formed consisting of titanium carbide with a metal binder based on solid solutions of iron and titanium in chromium.

Microstructure and mechanical behavior of cemented carbide with Al alloy binder fabricated by selective laser melting

Although cemented carbides have been increasingly investigated for additive manufacture, cemented carbides with low melting point metal binders have rarely been explored. In this study, a cemented carbide with AlSi10Mg alloy binder was fabricated by selective laser melting (SLM). The processing parameters were optimized through response surface methodology (RSM). The microstructure and mechanical properties of SLMed cast tungsten carbide (CC) - 40 wt% AlSi10Mg were studied. The SLMed carbide of CC - AlSi10Mg had much finer grain size of AlSi10Mg binder as compared with that of SLMed AlSi10Mg (1.9 μm vs. 7.3 μm). Noticeable metallurgical interaction between CC and AlSi10Mg binder was observed for SLMed carbide, which enhanced the bonding strength between CC and AlSi10Mg. SLMed carbide showed good Vickers hardness (236 ± 10 HV3), compression strength (639 ± 13 MPa), and abrasion wear resistance (0.47 ± 0.03 × 10−3 mm3N−1 m−1).