Bulk Material Properties Research Articles

In-situ alloying in powder bed fusion: The role of powder morphology

Abstract In-situ alloying has been proven as a cost-effective, flexible and advantageous method for laser powder bed fusion (LPBF). Novel alloy development and exploration of, for example high entropy alloys in additive manufacturing, can benefit from this, due to the large number of potential elemental combinations and graduations that can be alloyed in-situ at relatively low cost. However, studies to date have not reported the role of powder characteristics in mixed feedstocks, which may in turn have significant impacts on the process and resultant bulk material properties. This has not been explored with in-situ alloying in literature thus far. In the present work, 4 different powder blends were prepared, processed with LBPF and characterized to reveal the relationships between the particle size distribution (PSD), the powder morphology and their effect on the rheology, powder bed density, bulk density, microstructure and chemical homogeneity. For this purpose, various commercial and elemental powders with different morphology and PSD were used for powder blending. It is shown that a highly homogenous alloy can be created using spherical, bi-modally distributed powder containing between 21 and 30 vol%

Study on the Superhydrophobic Properties of an Epoxy Resin-Hydrogenated Silicone Oil Bulk Material Prepared by Sol-Gel Methods.

A superhydrophobic material was prepared by a simple and easily accessed sol-gel method using epoxy resin (E-51) and γ-aminopropyltriethoxysilane (KH-550) as the precursors, aqueous ammonia (NH4OH) as the catalyst and hydrogenated silicone oil (PMHS) as the hydrophobic modifier, and then pelleting the final product. The morphologies, surface chemical properties and thermal stability of the superhydrophobic bulk materials were characterized by scanning electron microscopy, Fourier infrared spectrometry and thermal analyzer. The hydrophobic properties and repairability of the as-prepared materials were also studied. The results showed that the prepared epoxy resin-hydrogenated silicone oil bulk materials were composed of tightly bound nanoparticles with a size of 50–100 nm in diameter. The material showed excellent superhydrophobic properties with a surface contact angle of 152°. The material also had good thermal resistance with a heat-resistant temperature of 300 °C and showed good repairability. The epoxy resin-hydrogenated silicone oil bulk superhydrophobic material exhibited excellent performance and showed wide application prospects.

Controlled release of micronutrients from surface-modified polymer films for agricultural applications

Active polyethylene/carbon black films with the capability of controlled release of micronutrients were developed in this work. A simple technique allowed modifying film surface through the incorporation of different mineral particles (talc, zeolite and calcium carbonate), without altering material bulk properties. Particle distribution and dispersion on surface were analyzed by scanning electron microscopy (SEM); meanwhile, particle concentration was determined by thermogravimetric analysis (TGA). Particle adhesion on films surface was also determined. Saturated solutions of different micronutrients sources (iron, copper and manganese sulfates) were sprayed separately on surface-modified films. SEM, elemental mapping by energy-dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD) were used to verify the presence of salts on modified films. Finally, release of micronutrients (salts) in distilled water was studied by flame atomic absorption spectroscopy (FAAS). Surface-modified films allowed a controlled release of copper and iron sulfates in water up to a minimum time of 5 weeks. However, the release of manganese could be prolonged up to 1 week. The obtained results could be promissory for the development of active agricultural films with the capability of releasing micronutrients in a controlled manner to satisfy the nutritional requirements of crops, mainly in depleted soils.

Characterization of Surface Fatigue Crack Nucleation and Microstructurally Small Crack Growth in High Strength Aluminum Alloys

It is well established that fatigue crack nucleation and small crack growth in high strength aluminum alloys are highly influenced by the surrounding microstructure including grain boundaries, texture, inclusion barriers, among other factors. As such, specific and targeted experimental and computational methods are necessary to accurately capture and predict the discrete behavior of microstructurally small fatigue cracks. In this study, surface fatigue crack nucleation and microstructurally small crack growth in high strength aluminum alloys, commonly used in aerospace applications, are evaluated through a holistic approach encompassing fatigue testing, crack measurement, and computational prediction of crack growth rates. During fatigue testing, crack shapes and growth are quantified using a novel surface replication technique that is applied to investigate crack nucleation, as well as to collect validation data that includes an accurate description of crack shape during crack propagation, a challenging and essential component in predicting crack growth. Computational simulation of fatigue crack growth in non-straight, complex surface crack arrays typically requires high fidelity analysis using computationally expensive methods to account for the mathematical and geometrical complexities inherent in the solution. A dislocation distribution based technique has been previously demonstrated to rapidly and accurately predict the stress intensity factors for through cracks of complex shape. This method was expanded and investigated as an approach for rapidly predicting the crack growth rate of kinked and tortuous surface crack arrays, using the crack configuration and bulk material properties as inputs. To investigate the accuracy and effectiveness of this characterization approach, surface crack growth in AA7075-T7351 was experimentally analyzed and modeled under high cycle and low cycle fatigue conditions. This comprehensive approach was determined to be an expedient and applicable method for characterizing and evaluating the nucleation and crack growth rate of non-planar microstructurally small and short crack configurations.

Where physics meets biology: More information

In his article “Does new physics lurk inside living matter?” (Physics Today, August 2020, page 34), Paul Davies mentions many interesting phenomena in biology, including epigenetic influence in two-headed worms. I agree that such information might be important to both physics and biology.11. J. J.-L. Ting, J. Appl. Phys. 125, 155702 (2019). https://doi.org/10.1063/1.5088852As I finished reading, I realized the article is advocating quantum biology. Davies cites a claim made by researchers in 2015 “that many biologically important molecules, such as sucrose and vitamin D3, have unique electron-conductance properties associated with the critical transition point between an insulator and a disordered metal conductor.”What I do not know is this: How could bulk material properties such as electron conductance be defined at the molecular level? In my opinion, geometry will be more important than material properties at that level.ReferenceSection:ChooseTop of pageReference <<CITING ARTICLES1. J. J.-L. Ting, J. Appl. Phys. 125, 155702 (2019). https://doi.org/10.1063/1.5088852, Google ScholarCrossref, ISI© 2021 American Institute of Physics.

Supraparticles for Sustainability

AbstractThe indispensable transformation to a (more) sustainable human society on this planet heavily relies on innovative technologies and advanced materials. The merits of nanoparticles (NPs) in this context are demonstrated widely during the last decades. Yet, it is believed that the impact of particle‐based nanomaterials to sustainability can be even further enhanced: taking NPs as building blocks enables the creation of more complex entities, so‐called supraparticles (SPs). Due to their evolving phenomena coupling, emergence, and colocalization, SPs enable completely new material functionalities. These new functionalities in SPs can be utilized to render six fields, essential to human life as it is conceived, more sustainable. These fields, selected based on an entropy‐rate‐related definition of sustainability, are as follows: 1) purification technologies and 2) agricultural delivery systems secure humans “fundamental needs.” 3) Energy storage and conversion, as well as 4) catalysis enable the “basic comfort.” 5) Extending materials lifetime and 6) bringing materials back in use ensure sustaining “modern life comfort.” In this review article, a perspective is provided on why and how the properties of SPs, and not simply properties of individual NPs or conventional bulk materials, may grant attractive alternative pathways in these fields.

Evolution of microscopic strains, stresses, and dislocation density during in-situ tensile loading of additively manufactured AlSi10Mg alloy

The AlSi10Mg alloy produced by laser powder bed fusion (LPBF) possesses a novel microstructure and higher mechanical properties compared with its casting counterpart. So far, the crystallographic orientation-dependent lattice strains, average phase stresses, and dislocation density during the tensile loading of the LPBF AlSi10Mg are not well understood. This fact is impeding further optimization of microstructure and mechanical properties. High energy synchrotron X-ray diffraction providing deep penetration capability and phase-specific measurements of various bulk properties of crystal materials is applied to investigate the LPBF AlSi10Mg under loading. The crystallographic orientation-dependent lattice strains and elastoplastic properties of the Al matrix are assessed. The average phase stresses are calculated to quantify load partitioning between the Al and Si phases. The nano-sized Si particles that bear high-stress are efficient strengthening particles. The maximum value of the average phase stress of Si reaches up to ~2 GPa. Based on the modified Williamson-Hall and the modified Warren-Averbach methods, the dislocation density and its evolution during the plastic deformation are determined. A multistage strain hardening behavior is detected in the Al matrix, which is associated with the interactions between the dislocations and the cell boundary network.

Discrete Seed Feeder Designing for Mobile Apparatus: Early Results for Pinus sylvestris L. Species

Discrete feeding of forest seeds is an urgent task for accurate detection of seeds during grading and reducing the seeding rate. The study used Pinus sylvestris L. seeds from cones collected in a natural stand of the Lisinsky educational-and-experimental forestry farm, Leningrad region, Russia, in 2017. Well-known methods for determining the properties of bulk materials were used; the results were processed by mathematical statistics using the MS Excel program. The physical and mechanical properties of uncalibrated seeds as a bulk material were determined. The angle of repose of Pinus sylvestris L. seeds, determined using a hollow cylinder by calculation, is 24.92°. The angle of repose of Pinus sylvestris L. seeds, determined using a hollow cylinder and a goniometer, is 32.7°. The significant discrepancy (~8°) in the values obtained by these methods is explained by the seeds shape. The flowability of Pinus sylvestris L. seeds corresponds to an excellent (free) category. The study will enable correct seed treatment protocols for sustainable forest management. However, some questions remained unresolved: how to orient a single seed in the right direction? How does seed-size calibration affect the angle of repose?

Algorithm for the determination of the angle of repose in bulk material analysis

As far as the calibration of bulk material for DEM simulations is concerned, it is necessary to adjust the properties of simulated bulk material until the behaviour of this digitally modelled material coincides with the behaviour of physical material tested in laboratory tests. One well-established parameter that is often used for this purpose is the so-called angle of repose, which can be described as the highest possible angle, with respect to the horizontal plane, at which bulk material can be heaped without collapsing. For the determination of this angle, various kinds of tests are applicable, such as the commonly used lifting cylinder test, in which a bottomless cylinder filled with bulk material is lifted off the ground. Digital bulk material calibration regarding the angle of repose is then performed using DEM simulations and adjusting the influencing material parameters correspondingly until the same angle of repose is obtained with the digital and thus calibrated bulk material model.Since the angle measurement is still mostly done by hand, which harbours the danger of errors, and the calibration process with altering angle measurement and parameter adjustment is rather time-consuming, the development of an algorithm for the evaluation of the angle of repose promises some significant advantages. To name a few: higher reproducibility and accuracy of measurements, by eliminating the factor human; faster calibration due to a well-defined evaluation process, also implementable as algorithms directly in calibration processes; and benefits due to statistically supported, time-efficient analysis of large amounts of data.This paper gives a step by step explanation of the methods behind the developed algorithm for the determination of the angle of repose, in particular, in order to enable the implementation of these methods as tools in custom software programs. Thus the developed algorithm is useful for applications ranging from simple angle determination to fully automated calibration procedures etc.

Modeling Cotton Module Builder and Loader to Enhance Biomass Testing

HighlightsPhysical models of module builder and module loader were developed to enhance biomass testing with reduced mass and volume of biomass.Models used dimensional analysis, Pi Terms, and engineering factors and emphasis on reduced module upsetting and disturbance.Some engineering terms such as tamping face pressure and velocity, and particle size were not scaled to reduce biological-material distortions.Switchgrass bulk density at 8% wet basis for prototype and model were 115 and 80 kg m-3, respectively.Abstract. The objective was to design and implement separate models of a first-generation cotton module builder and a module loader that facilitated tamping quasi-confined biomass and the minimal disturbances of modules during emptying from the builder and during loader operations including unloading. The 122-cm long model, compared to 978-cm long prototype, reduced the mass of module contents required for testing from 6188 to 44 kg, or by a factor of 141:1. The tamping process was emphasized with constant tamper pressure of 76.6 kPa applied to module contents for prototype and model. Consistent properties such as SG characteristic length were also held constant among module sizes to reduce the complications of introducing un-anticipated biological-material distortions. Similarities in design aspects beyond dimensional analysis were emphasized to reduce inadvertent module upset and disturbance. Hydraulics ensured uniform tamping and lifting. An efficient module box for the model resembled the prototype-scale commercial unit with z-shaped ribs and upward-tapered module sides. Seed cotton [8% moisture wet basis (w.b.)] bulk densities for prototype and model were 166 and 107 kg m-3, respectively. Bulk densities for switchgrass (8% w.b.) prototype and model were 115 and 81 kg m-3, respectively. Reduced bulk density of models was attributed to essentially no external confinement stresses being applied to modules at rest resulting in only self-imposed confinement stresses due to module content over-burden. However, unconfined modules may have a role in handling biomass for reduced distances. Also related to minimizing module upsetting, module loading emphasized the counter-motions of advancing the loader versus the conveyor motion in the opposite direction, all driven with an electric motor. Module stability during loading was attributed to a self-imposed normal stress of module weight acting downward onto a horizontal plane of the module. The fixed loading angle of 15° and material bulk properties were held constant between prototype and model. Dependent variable for the module loader was normal stress for module stability. Normal stresses resulting from seed cotton at 8% moisture content (wet basis) were 4.754 and 0.637 kPa, respectively. Normal stresses for chopped SG at 8% moisture content (wet basis) were 3.302 and 0.484 kPa, respectively. Biomass modules would not be as stable as cotton modules based on normal stress, and due to lack of intermeshing cotton fibers. Results of loading and unloading a dozen SG model modules resulted in one module failure due to upset, and that was attributed to a 2-layer fill versus 3-layer fill for that one module. Keywords:

Bending analysis of the multi-phase nanocomposite reinforced circular plate via 3D-elasticity theory

In this article bending response of multi-phase nanocomposite (MPC) filled by circular plates (MPCCP) in the framework of the three-dimensional elasticity model under bi-directional initially stressed (BDIS) resting on non-polynomial elastic foundation for a broad range of boundary conditions is presented. The discrete singular convolution (SS-DSC) based on state-space is provided to evaluate the bending characteristics of MPCCP by considering various boundary conditions. Halpin–Tsai model and micro-scaled fibers have been applied in the hierarchy to anticipate the properties of bulk material of the multiscaled composites. In order to model a disk, singular point has been analyzed. The graphene platelets (GPLs) are assumed to be oriented in random directions and distributed in uniform pattern in the epoxy resin matrix. Then, to provide the influences of primary stressed, elastic substrate and a range of pressure types on the bending behavior of the MPCCP, a parametric analysis has been conducted. Computational outcomes disclose that sinusoidal load is the best pressure for improving the deformation resistances and stress of the nanocomposite circular/annular plates.

Justification of vibrating hopper hole parameters during fine grained bulk material unloading

Purpose. The leakage process of the fine grained bulk material (BM) from the unloading hopper is considered. As known the BM behaviour during the unloading process is directly related to the material stress state (active or passive) inside the hopper, which depends on the physical and mechanical bulk material properties, as well as hopper geometric parameters. At the boundary of the transition from the cylindrical part to the conical part of the unloading hopper hole, the horizontal stresses that precede the leakage of the material increase sharply. The use of vibration reduces horizontal stresses in the hopper and thus improves the bulk product fluidity. Also, the use of vibration reduces the probability of the free-fall arch formation over the outlet. Therefore, the present paper is aimed at developing the mathematical model of the fine grained bulk material flow under the vibration action from the conical hopper hole. Methodology. It is used one of the methods of studying the BM behavior, namely the analysis of the stress state of the conditionally stationary (pseudo-stationary) layer of the product and the force balance equation in the free-fall arch is made for further study of the geometric parameters of the unloading hole. Findings. In this paper, the mathematical model of the BM behavior in the conical hopper hole is developed. Since the most determining factor influencing the hopper productivity is the outlet diameter, so based on the developed model, it is established relationships that allow determining all parameters that affect the diameter. Graphical dependences are obtained, which allow to estimate the influence of the angle inclination of the hopper hole walls on the value of the hopper outlet size at active and passive stress states. The dependence of the diameter of the unloading hopper hole on the BM properties is also established. The BM properties directly affect the initial shear resistance of the material. The influence of vibration on the unloading hole geometry is presented. Originality. The pseudo-immobile layer of bulk product is considered in the developed mathematical model, and it is investigated how vibration affects the BM behavior in this layer. Practical value. The practical value of this paper lies in the possibility of further mathematical modeling of the influence of the BM properties, hopper geometric dimensions and vibration on the product behavior in the material leakage process from the hopper. The results of the studies, presented in the form of graphs, can be used during the vibrating hopper design and the selection of rational modes of hopper operation.

Relaxation of residual stress in fused filament fabrication part with in-process laser heating

Fused filament fabrication (FFF) has become a preferred method for additive manufacturing due to its cost-effectiveness and flexibility. However, the parts built using FFF process suffer from lower mechanical strength compared to that fabricated using traditional method. In this work, an in-process laser heating method was presented to heal residual stress, therefore improve mechanical behavior along in-plane direction. The enhancement in tensile strength and elongation of fabricated samples with the utilization of laser heating have been demonstrated. In addition, models and hypothesis on the transformation of microstructure were proposed and verified by experimental data. With the utilization of laser pre-deposition heating, tensile strength of printed polyether ether keton (PEEK) part along in-plane direction increased by 11.4%, thus reached 93.5% that of the bulk material property. The fracture behavior was also altered from brittle to stretchable with visible necking effect, backed up with both tensile curve and scanning electron microscope images independently.

Impact of particle size distribution of material on pneumatic conveying operation on example of ground phosphate

Phosphates are essential in the agricultural sector and about 95% of the world production is used in fertilizer industry. After grinding, phosphate ore, as well as any other bulk material is required to be transported to further processing. Pneumatic conveying systems are preferred over other mechanical systems due to their usage convenience. Different types of phosphate rocks, as well as other just seemingly the same materials, may widely differ in their characteristics. Therefore, physical properties of bulk material must be taken into the consideration to achieve reliable pneumatic conveying system operation and avoid possible problems. This paper will address problems with pneumatic conveying of ground phosphate that occurred in fertilizer production plant.

Measurement of thermal properties of bulk materials and thin films by modulated thermoreflectance (MTR)

Thermal conductivity and thermal diffusivity of materials must be known at high accuracy for thermal engineering applications, in order to understand energy dissipation in devices and engines. Thermal conductivity libraries can be unreliable since their reported values may not reflect the complexities of the samples under investigation, and new materials may not yet be listed. Over the past three decades, modulated thermoreflectance (MTR) has emerged and evolved as a reliable, non-contact, and noninvasive technique to measure the thermal properties of a wide range of bulk and thin film materials and their interfaces. This Tutorial discusses the basis of, and recent advances in, the MTR technique, and its applications in the thermal characterization of a variety of materials. MTR experiments use two micrometer-wide laser beams. Experimental data (amplitude and phase vs the offset between the pump and the probe) give information about heat diffusion around the heat source along several tens of micrometers. Heat diffusion equations are used to fit the experimental data and extract the required thermal properties. Importantly, best fit procedures are not always needed because some analytical approximations provide evidence of the required thermal properties. We present many examples (bulk materials, layered sample, etc.) which illustrate this.

Overview and comparison of modelling methods for foams

Cellular materials, especially foams, are widely used in several applications because of their special mechanical, electrical and thermal properties. Their properties are determined by three factors: bulk material properties, cell topology and shape as well as relative density. The bulk material properties include the mechanical, thermal and electrical properties of the matrix. The cell topology determines if the foam exhibits stretch or bending dominated behaviour. The relative density corresponds to the foaming degree. It is defined by the cell edge length and cell wall thickness. Especially for the linear elastic properties there are many different modelling approaches. In general, these methods can be divided into two groups namely direct modelling, e.g. analytical and finite element models and constitutive modelling, e.g. models which are generated through homogenization methods. This paper presents an overview of the different modelling methods for foams. Furthermore, sensitivity studies are presented which enable the comparison of the models with regard to the estimation of the elastic properties, show the limits of those models and enable the investigation of the influence of the above mentioned factors on the elastic properties. Selected models are validated with experimental data of a low density foam regarding the Young’s modulus.

Homogeneous superconducting gap in DyBa2Cu3O7−δ synthesized by oxide molecular beam epitaxy

Much of what is known about high-temperature cuprate superconductors stems from studies based on two surface analytical tools, angle-resolved photoemission spectroscopy (ARPES) and spectroscopic imaging scanning tunneling microscopy (SI-STM). A question of general interest is whether and when the surface properties probed by ARPES and SI-STM are representative of the intrinsic properties of bulk materials. We find this question is prominent in thin films of a rarely studied cuprate DBCO. We synthesize DBCO films by oxide molecular beam epitaxy and study them by in situ ARPES and SI-STM. Both ARPES and SI-STM show that the surface DBCO layer is different from the bulk of the film. It is heavily underdoped, while the doping level in the bulk is close to optimal doping evidenced by bulk-sensitive mutual inductance measurements. ARPES shows the typical electronic structure of a heavily underdoped CuO2 plane and two sets of one-dimensional bands originating from the CuO chains with one of them gapped. SI-STM reveals two different energy scales in the local density of states, with one corresponding to the superconductivity and the other one to the pseudogap. While the pseudogap shows large variations over the length scale of a few nanometers, the superconducting gap is very homogeneous. This indicates that the pseudogap and superconductivity are of different origins.

A semi-analytical study on the nonlinear pull-in instability of FGM nanoactuators

In this paper, a new semi-analytical solution for estimating the pull-in parameters of electrically actuated functionally graded (FG) nanobeams is proposed. All the bulk and surface material properties of the FG nanoactuator vary continuously in thickness direction according to power law distribution. Here, the modified couple stress theory (MCST) and Gurtin-Murdoch surface elasticity theory (SET) are jointly employed to capture the size effects of the nanoscale beam in the context of Euler-Bernoulli beam theory. According to the MCST and SET and accounting for the mid-plane stretching, axial residual stress, electrostatic actuation, fringing field, and dispersion (Casimir or/and van der Waals) forces, the nonlinear nonclassical equation of motion and boundary conditions are obtained derived using Hamilton principle. The proposed semi-analytical solution is derived by employing Galerkin method in conjunction with the Particle Swarm Optimization (PSO) method. The proposed solution approach is validated with the available literature. The freestanding behavior of nanoactuators is also investigated. A parametric study is conducted to illustrate the effects of different material and geometrical parameters on the pull-in response of cantilever and doubly-clamped FG nanoactuators. This model and proposed solution are helpful especially in mechanical design of micro/nanoactuators made of FGMs.

Fatigue of carburised CrNiMo steel: Testing and modelling concept

AbstractIn this study, a testing and modelling concept is presented, aimed at estimating the local fatigue properties of carburised CrNiMo steel, covering the fatigue limit under axial and torsional loading at various mean stresses. Aimed at predicting the bulk material properties, all specimens were ultrasonic shot‐peened prior to testing. Fractographic analyses were conducted on all specimens using scanning electron microscopy to define the type, size and chemical composition of crack initiation‐related discontinuities. An iteration of the FKM guideline is presented, relying on the external notch concept to explain the effect of large internal notches on the mean stress sensitivity.

(Invited) Solid State Sodium Satteries: From Solid Electrolytes to Functional Device

Li-ion batteries (LIBs) dominate the electrochemical energy storage technology because of their extraordinary performance, high energy density, and long cycle life. Still, the enormously growing demand of Li due to the expanding market raises concerns about the costs and the availability of lithium in the future, necessitating the development of beyond-lithium electrochemical energy storage concepts. Sodium is among the most investigated alternatives for lithium due to its abundance, widespread availability and much lower costs. The simple replacement of lithium with sodium in liquid electrolyte cells while keeping otherwise similar cell design results however in lower energy densities as compared to LIBs due to a higher molar mass, more positive redox potential and higher reactivity of sodium with liquid electrolytes as compared to lithium. In combination with solid electrolytes, however, much higher energy densities can be expected due to a possible use of metallic sodium as an anode instead of currently used hard carbons, opening new perspectives for the development of Na-based electrochemical energy storage systems.Sodium is among the most investigated alternatives for lithium due to its abundance, widespread availability and much lower costs. The simple replacement of lithium with sodium in liquid electrolyte cells while keeping otherwise similar cell design results however in lower energy densities as compared to LIBs due to a higher molar mass, more positive redox potential and higher reactivity of sodium with liquid electrolytes as compared to lithium. In combination with solid electrolytes, however, much higher energy densities can be expected due to a possible use of metallic sodium as an anode instead of currently used hard carbons, opening new perspectives for the development of Na-based electrochemical energy storage systems.Fundamental prerequisite for the development of high-performance solid state sodium batteries is a sufficiently high total conductivity of all its components at room temperature. The latter includes the ionic conductivity of the electrolyte (simultaneously acting as a separator in solid state batteries), the combined electronic/ionic conductivity of the cathode and the anode half-cells, as well as a high conductivity of key interfaces between the electrolyte and the electrode materials. The total conductivity critically relies on the bulk properties of individual materials, but also on their nanomorphology in the component assemblies as well as on the processing- and operation-dependent interface between the materials. The materials challenge therefore goes far beyond the bulk structure level, including the other fundamental aspects of materials chemistry (such as integration of materials into components, optimization of component microstructure, interface properties), electrochemistry (individual contributions to the total impedance, degradation mechanisms upon cell operation), and engineering (development of processing technology enabling fabrication of optimized components).I will give an overview of the sodium solid state battery development that spans from the development of solid state sodium conductors to their processing to functional battery components and finally to the fabrication and testing of the complete cells. I will discuss bottlenecks in the battery performance and will show the concepts for the mitigation of critical steps.