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NASA NTRS2019

Metallized Plastic Current Collectors

Metallized plastic current collectors are an innovation patented by the Soteria Battery Innovation Group with the promise of isolating active material involved in an internal short by vaporizing and isolating the short from the rest of the cell electrode jellyroll or stack. Partnering with NREL, UCL, Coulometrics, and Soteria, NASA is leading a research effort into demonstrating the merits and understanding the phenomena of this safety innovation using prototype 18650 cylindrical cells vs control cells with standard metal foil current collectors. Cells with and without the plastic collector, with and without the on-demand internal short circuit device, and with polymer or cellulose separators were made. Safety evaluations were done with driving cells into thermal runaway (TR) with thermal and nail penetration triggers while inside our TR calorimeter and with ultra high speed X-ray videography provided at Synchrotrons. Preliminary results suggests that the thermally unstable plastic current collector innovation has great promise for preventing TR or reducing the severity of the TR output.

Li-ion cell↗

DOE OSTI2017

Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Plastics and Rubber Manufacturing

Energy bandwidth studies can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities in U.S. manufacturing. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. plastics and rubber products manufacturing. The study relies on multiple sources to estimate the energy used for processes in five plastics and rubber manufacturing subareas, representing 97% of sector-wide energy consumption in 2010. Energy savings opportunities for the subareas studied for various plastics and rubber products are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

energy energy bandwidth study, plastics, rubber, a↗

DOE OSTI2017

Mathematical Calibration of Modular Plastic Scintillators for Various Assay Applications - 17322

Plastic scintillators provide an inexpensive option to assay and characterize radioactive material. Due to the low cost it is generally possible to an array of large numbers of plastic scintillators to achieve high measurement efficiencies. The beta only thin plastic scintillators used in the Argos contamination monitors provide a convenient and reliable scintillator package that can be grouped together to form an assay system. Mathematical calibrations, using MCNP, have been produced for this detector that allow for rapid construction of various custom measurement geometries. The calibrations were constructed by comparing a series of measurements made with a number of beta and beta/gamma emitting nuclides. Characterization of the beta scintillators utilized beta emitting nuclides that included spectra from low average energy, e.g. C-14, to relatively high average energy, e.g. Sr/Y-90. In order to perform the calibration, custom versions of the standard Argos scintillators were produced that provide an MCA output for spectroscopic investigation. The spectra were then compared to detailed MCNP models in an iterative process to energy calibrate and efficiency calibrate each detector type. The validated models and energy calibrations were then tested against a number of volumetric geometries to confirm that the model would translate well to any other geometry. These validated models can then be used to rapidly construct custom measurement geometries for material measurement and screening. Two examples of measurement applications include a beta screening system for dirt on a conveyor belt and a flow through beta liquid assay system. The mathematical calibration process, validation results, and a number of application examples are discussed. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2024

A Primer on Using Analysis to Guide Plastic Circularity

BOTTLE, funded by DOE's Advanced Materials & Manufacturing Technologies Office and Bioenergy Technologies Office (BETO), conducts analysis-guided R&D to change the way we recycle plastics. But what does analysis really mean? In this webinar, BOTTLE Analysis Co-Lead Dr. Taylor Uekert, a researcher with the National Renewable Energy Laboratory (NREL), will introduce key analysis techniques such as techno-economic analysis, life cycle assessment, and environmental justice evaluation. Relevant to both analysts and non-analysts, Dr. Uekert will cover the basics of analysis techniques and discuss how these methods are conducted and interpreted. She will provide examples from the BOTTLE portfolio demonstrating their use in benchmarking and optimizing the costs and environmental impacts of new innovations in plastic redesign and recycling. If you are working in the plastics recycling field - from experimental work to analysis to community-focused projects - you won't want to miss this talk. The webinar will end with a Q&A session.

analysis↗

DOE OSTI2022

An Eulerian crystal plasticity framework for modeling large anisotropic deformations in energetic materials under shocks

Here, this paper demonstrates a novel Eulerian computational framework for modeling anisotropic elastoplastic deformations of organic crystalline energetic materials (EM) under shocks. While Eulerian formulations are advantageous for handling large deformations, constitutive laws in such formulations have been limited to isotropic elastoplastic models, which may not fully capture the shock response of crystalline EM. The present Eulerian framework for high-strain rates, large deformation material dynamics of EM incorporates anisotropic isochoric elasticity via a hypo-elastic constitutive law and visco-plastic single-crystal models. The calculations are validated against atomistic calculations and experimental data and benchmarked against Lagrangian (finite element) crystal plasticity computations for shock-propagation in a monoclinic organic crystal, octahydro-1,3,5,7-tetranitro-1,3,5,7 tetrazocine (β-HMX). The Cauchy stress components and the resolved shear stresses calculated using the present Eulerian approach are shown to be in good agreement with the Lagrangian computations for different crystal orientations. The Eulerian framework is then used for computations of shock-induced inert void collapse in β-HMX to study the effects of crystal orientations on hotspot formation under different loading intensities. The computations show that the hotspot temperature distributions and the collapse profiles are sensitive to the crystal orientations at lower impact velocities (viz., 500 m/s); when the impact velocity is increased to 1000 m/s, the collapse is predominantly hydrodynamic and the role of anisotropy is modest. The present methodology will be useful to simulate energy localization in shocked porous energetic material microstructures and other situations where large deformations of single and polycrystals govern the thermomechanical response.

42 ENGINEERING↗

DOE OSTI2024

Low-velocity impact resistance and failure characteristics of all thermoplastic woven polymer-fiber-reinforced plastic composites

This study addresses the impact performances of recyclable composites made of all thermoplastic polymer-fiber-reinforced plastics (PFRPs), where the reinforcing fibers and matrix are made of thermoplastic polymers. Three woven PFRPs systems were evaluated, including polypropylene fibers, polypropylene matrix, and high-density polyethylene matrix. In low-velocity impact scenario with an impactor speed of less than 6 m/s, our results demonstrate the energy absorption capabilities of the flat laminate PFRPs compared to woven carbon fiber-reinforced plastics (CFRPs) and aluminum alloy 5052. For the systems studied, the PFRPs can reach the specific energy absorption 89% to 115% of the CFRPs. Even compared with the aluminum alloy 5052, the PFRPs can reach up to 97%. We investigate the failure morphologies of the PFRPs using X-ray µCT scans. They reveal the PFRPs’ unique ductile failure morphologies compared to common CFRPs. In addition, we heal the perforated region in the PFRPs by applying the manufacturing process identical to the initial curing process. The healed panels are perforated again, and they recovered 30% to 38% of their original specific energy absorption, a recovery not achievable with CFRPs. This study provides valuable experimental results, and concrete insights into the potential applications of recyclable PFRPs in various engineering fields. It emphasizes their excellent energy-absorbing capability and repairability.

CFRPs↗

DOE OSTI2024

Unraveling the Highly Plastic Behavior of ALD-Aluminum Oxide Encapsulations by Small-Scale Tensile Testing

We present a study directly measuring the electron-beam-induced plasticity of amorphous Al 2 O 3 coatings. Core–shell nanostructures are employed as small-scale model systems for two-dimensional coatings made by atomic layer deposition (ALD). Copper nanowires (NWs) are used as substrates for ALD deposition, representing a model system for interconnects commonly found in integrated circuits. Experiments are performed in situ in a transmission electron microscope (TEM) and further analyzed with electron energy loss spectroscopy (EELS). Our in situ TEM tensile experiments reveal the highly plastic behavior of the ALD shell, which withstands a maximum strain of 188%. Comparable samples under beam-off conditions show a brittle fracture, which underlines the effect of electron irradiation. The electron-beam-activated bond switching within the amorphous network enables compensation of the applied tensile strain, leading to viscous flow. By incorporating an intermediate nanocrystalline layer within the Al 2 O 3 shell, the plasticity is suppressed and brittle fracture occurs. This work directly demonstrates the tuning of mechanical properties in amorphous ALD structures through electron irradiation.

36 MATERIALS SCIENCE↗

DOE OSTI2018

High-Z Sensitized Plastic Scintillators: A Review

The need for affordable and reliable radiation detectors has prompted significant investment in new radiation detector materials, due to concerns about national security and nuclear nonproliferation. Plastic scintillators provide an affordable approach to large volume detectors, yet their performance for high-energy gamma radiation is severely limited by the small radiation stopping power inherent to their low atomic number. Although some sensitization attempts with organometallics were made in the 1950s to 1960s, the concomitant decrease in light yield has limited the usefulness of these sensitized detectors. Recently, with new knowledge gained during the rapid development of organic optoelectronics and nanotechnology, there has been a revived interest in the field of heavy element sensitized plastic scintillators. In this paper, the recent efforts on sensitized plastic scintillators are summarized. Basic scintillator physics is first reviewed. The discussion then focuses on two major thrusts in the field: sensitization with: (1) organometallics and (2) oxide and fluoride nanoparticles. The design rationales and major results are examined in detail, with existing limitations and possible future pathways discussed. Lastly, special attention is paid to the underlying energy deposition and transfer processes, as these determine the key performance metrics such as light yield and radioluminescence decay lifetime.

36 MATERIALS SCIENCE↗

DOE OSTI2018

A New Version of the Lithium Ion Conducting Plastic Crystal Solid Electrolyte

Abstract Portable electronic devices are predominantly powered by lithium ion batteries in which the electrolyte is a liquid or gel of lithium salts dissolved in molecular solvents. There have been many attempts to replace the flammable liquid component of the electrolyte by alternative alkali metal transporting media, such as superionic crystals, alkali‐conducting glassy solids, ionic liquids, salt‐in‐molecular plastic crystal solvent, and salt‐in‐ionic plastic crystal solvents. Except for the first two of the above, which have their own problems, all the above have the disadvantage that the alkali cation is the least mobile of the ionic species due to its high charge/radius ratio. Here, some new, silylsulfate‐based are introduced. Members of the class of lithium ion conductor in which the alkali ion is the only cationic species present, and the salt itself is a plastic crystal, a solid in which the anion centers of mass are ordered, but the anion orientations are disordered and dynamic (best example NaCB 9 H 10 , see text). It is shown that depending on the nature of the anion, the conductivity may be within a factor of two of the standard liquid carbonate electrolyte. The soft, spreadable electrolyte, impregnated in Celgard separators, supports truly reversible Li insertion into the LiCoO 2 cathode.

Klein, Iolanda S.↗

DOE OSTI2017

A Plastic–Crystal Electrolyte Interphase for All‐Solid‐State Sodium Batteries

Abstract The development of all‐solid‐state rechargeable batteries is plagued by a large interfacial resistance between a solid cathode and a solid electrolyte that increases with each charge–discharge cycle. The introduction of a plastic–crystal electrolyte interphase between a solid electrolyte and solid cathode particles reduces the interfacial resistance, increases the cycle life, and allows a high rate performance. Comparison of solid‐state sodium cells with 1) solid electrolyte Na 3 Zr 2 (Si 2 PO 4 ) particles versus 2) plastic–crystal electrolyte in the cathode composites shows that the former suffers from a huge irreversible capacity loss on cycling whereas the latter exhibits a dramatically improved electrochemical performance with retention of capacity for over 100 cycles and cycling at 5 C rate. The application of a plastic–crystal electrolyte interphase between a solid electrolyte and a solid cathode may be extended to other all‐solid‐state battery cells.

Gao, Hongcai↗

DOE OSTI2021

New Technologies are Needed to Improve the Recycling and Upcycling of Waste Plastics

In their Editorial to the Special Issue on The Chemistry of Waste Plastics Upcycling, the Guest Editors Adam Guss, George Huber, Carol Lin, Xianzhi Meng, Hugh O'Neill, Arthur Ragauskas, Jia Wang, Yanqin Wang, and Frederik Wurm highlight some of the increasingly urgent efforts being made by chemists to address challenges related to the fate of plastics at the end of, their useful lives and the valorization of plastic waste.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Multiscale plasticity of geomaterials predicted via constrained optimization‐based granular micromechanics

Abstract A general framework to derive nonlinear elastic and elastoplastic material models from granular micromechanics is proposed, where a constraint‐based variational structure is introduced to classical grain contact‐based homogenization methods of hyperelasticity. Like the classical hyperelastic methods, reference solutions for closed‐form hyperelastic material models are analytically derived from the grain‐scale contact mechanics. However, unlike prior methods, the proposed homogenization framework defines closed‐form hyperelastoplastic material models that extend multiscale variational methods to granular plasticity. The proposed framework is used to develop novel granular micromechanics‐based macroscopic models for a Mises type solid, Drucker–Prager type plasticity, and grain‐contact cohesive‐debonding with a deviatorically and volumetrically coupled nonlinearly elastic response. Macroscopic plastic parameters and yield criteria are explicitly related to their microscale counterparts, for example, the friction coefficient governing intergranular slip. Numerical examples and comparison to measurements from the literature, including triaxial compaction of concrete, are provided to investigate model predictions and demonstrate calibration to experimental data.

Bryant, E. C.↗

DOE OSTI2025

Bulk nanocrystalline Al–Mg–Y alloys with amorphous grain boundary complexions display high strength and compressive plasticity

Although nanocrystalline alloys regularly exhibit high strengths, their use in structural applications often face challenges due to sample size limitations, unstable microstructures, and the limited ability to plastically deform. The incorporation of amorphous grain boundary complexions has been proposed to address these issues, by simultaneously stabilizing nanocrystalline grain structures for scale-up processing and improving alloy toughness. In the present study, the mechanical behavior of bulk nanocrystalline Al–Mg–Y is examined with macroscale compression testing, probing a length scale that is relevant to real-world structural applications. Bulk samples were fabricated via a simple powder metallurgy approach, with different hot-pressing temperatures and durations employed for consolidation in order to investigate microstructural and property evolution. All of the specimens contained primary face-centered cubic Al and secondary Al 4 C 3 and Al 3 Y phases, with the Al 3 Y particles exhibiting two populations of small equiaxed and larger elongated particles. Appreciable plasticity was measured along with high ultimate stresses over 800 MPa due to the presence of amorphous grain boundary complexions. Microstructural characterization of fracture surfaces revealed that the area fraction of dimpled regions increased with longer hot-pressing time. Most importantly, the elongated Al 3 Y particles formed regular cellular patterns with increasing hot-pressing time, delaying shear localization and significantly enhancing plasticity. The hierarchy present in the microstructure of the Al–Mg–Y alloy, from amorphous grain boundary complexions to secondary phases, gives rise to excellent bulk mechanical properties, which are attractive for structural applications.

Bulk nanocrystalline alloy↗

DOE OSTI2016

Onset of Plasticity via Relaxation Analysis (OPRA)

In crystalline metals and alloys, plasticity occurs due to the movement of mobile dislocations and the yield stress for engineering applications is traditionally quantified based on strain. The onset of irreversible plasticity or “yielding” is generally identified by a deviation from linearity in the stress-strain plot or by some standard convention such as 0.2 % offset strain relative to the “linear elastic response”. In the present work, we introduce a new methodology for the determination of the true yield point based on stress relaxation. We show experimentally that this determination is self-consistent in nature and, as such, provides an objective observation of the very onset of plastic flow. Lastly, our designation for yielding is no longer related to the shape of the stress-strain curve but instead reflects the earliest signature of the activation of concerted irreversible dislocation motion in a test specimen under increasing load.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Bounds on the Rate-Dependent Plastic Flow of Tantalum up to 75 GPa

In this study we report on the continued development of thermodynamics-based analysis of shock waves propagation with the objective of extracting information related to materials strength at high strain rates and pressures. Building on previous results reported for peak stresses of 10 GPa and 25 GPa, we present a series of three-step gas-gun shock experiments designed to explore the pressure and strain rate dependence of plastic flow in polycrystalline tantalum. These experiments at nominal peak stresses of 50 GPa and 75 GPa show the irreversible deformation before pullback to be almost entirely confined to the shock loading, with negligible plastic relaxation on the post-shock plateau. We also add a reverse-ballistics shot at 25 GPa, which was designed to reveal the pullback response with negligible interference from free-surface effects. General thermodynamic considerations allow us to place bounds on the plastic behavior even for parts of the curve that change far too rapidly for the velocimetric time resolution of (conservatively) ~ 5 ns. To analyze the data, we found it necessary to substantially improve the interpolation/extrapolation scheme in order to improve its robustness, flexibility and range of applicability. We describe the new scheme based on splines, as well as an extension of free-surface corrections to the post-shock rarefaction waves. Reanalysis with the new scheme produces results essentially within the error bars previously reported, showing that the known systematic errors associated with free-surface effects are relatively inconsequential for determining thermodynamic paths.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2014

Plastic deformation in nanoindentation of tantalum: A new mechanism for prismatic loop formation

Here, the mechanisms of deformation under a nanoindentation in tantalum, chosen as a model body-centered cubic (bcc) metal, are identified and quantified. Molecular dynamics (MD) simulations and indentation experiments are conducted for [1 0 0], [1 1 0] and [1 1 1] normals to surface orientations. The simulated plastic deformation proceeds by the formation of nanotwins, which rapidly evolve into shear dislocation loops. It is shown through a dislocation analysis that an elementary twin (three layers) is energetically favorable for a diameter below ~7 nm, at which point a shear loop comprising a perfect dislocation is formed. MD simulations show that shear loops expand into the material by the advancement of their edge components. Simultaneously with this advancement, screw components of the loop cross-slip and generate a cylindrical surface. When opposite segments approach, they eventually cancel by virtue of the attraction between them, forming a quasi-circular prismatic loop composed of edge dislocation segments. This “lasso”-like mechanism by which a shear loop transitions to a prismatic loop is identified for both [0 0 1] and [1 1 1] indentations. The prismatic loops advance into the material along $\langle$1 1 1$\rangle$ directions, transporting material away from the nucleation site. Analytical calculations supplement MD and experimental observations, and provide a framework for the improved understanding of the evolution of plastic deformation under a nanoindenter. Dislocation densities under the indenter are estimated experimentally (~1.2 × 10 15 m -2 ), by MD (~7 × 10 15 m -2 ) and through an analytical calculation (2.6–19 × 10 15 m -2 ). Considering the assumptions and simplifications, this agreement is considered satisfactory. MD simulations also show expected changes in pile-up symmetry after unloading, compatible with crystal plasticity.

36 MATERIALS SCIENCE↗

DOE OSTI2019

The role of elastic and plastic anisotropy in intergranular spall failure

Recent mesoscale experimental observations of dynamic ductile failure have demonstrated a strong relationship between grain boundary (GB) misorientation and the likelihood of failure initiation along said GB. This correlation has been attributed to inherent GB weakness of particular misorientation. Here we discuss the role played by mechanics, i.e. elastic and plastic anisotropy, on the experimental observation. We make use of a recently developed framework for modeling dislocation-based crystal plasticity and ductile failure of single crystals under dynamic loading (CPD-FE). Polycrystals are studied at the mesoscale level through the explicit resolution of individual grains, i.e. resolving each individual grain's size, shape, and orientation. In our simulations, failure naturally localizes along the GBs with no necessity for ad hoc rules governing damage nucleation. We carry out a few thousand mesoscale calculations, systematically varying the misorientation angles of the GB in the computational microstructure. Despite the fact that we neglect the possibility of variations in inherent GB weakness, our simulations agree favorably with the experimental observations, implying that stress concentration generated by elastic and plastic anisotropies across GBs is a dominant governing factor in this phenomenon. Lastly, we find that misorientation angle is an insufficient GB descriptor to predict the likelihood of intergranular spall failure, which is better understood through the consideration of additional GB degrees of freedom.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Prismatic-to-basal plastic slip transition in zirconium

Here, we model three-dimensional dislocation ensembles in Zr pillars using newly developed mobility laws for dislocations on prismatic and basal planes. The effects of the loading orientation and temperature on the micro-scale mechanical response of single crystals are systematically explored. Easy dislocation glide is observed on prismatic planes, while hard glide occurs on basal planes. By selection of sample temperature and loading orientation, we show that the transition from prismatic to basal glide of dislocation ensembles can be controlled. We also show that the presence of dislocation cross-slip strongly promotes prismatic glide as a result of prismatic/basal cross-slip energy asymmetry. Cross-slip does not alter the occurrence of plastic slip transition but only induces a shift towards higher temperatures. The preponderance of plastic slip on basal or prismatic planes is found to be mediated by a transitional dislocation, which is composed of glissile segments on parallel prismatic planes connected by glissile super-jogs on basal planes. These findings provide a mechanistic understanding of experiments and highlight the significance of transitional prismatic-basal dislocations on the macroscopic characteristics of plasticity in HCP crystals.

36 MATERIALS SCIENCE↗