Materials Science & Engineering Research Works

Permanent URI for this collectionhttp://hdl.handle.net/1903/1660

Browse

Now showing 1 - 20 of 43

3-(4-Amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole
(MDPI, 2014-05-22) Pagoria, Philip; Zhang, Maoxi; Racoveanu, Ana; DeHope, Alan; Tsyshevsky, Roman V.; Kuklja, Maija M.
The title compound 3-(4-amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (ANFF-1) was synthesized by: (1) by reaction of 3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (BNFF-1) with gaseous ammonia in toluene and (2) by partial oxidation of 3,4-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (BAFF-1) with 35% H2O2 in concentrated H2SO4.
A Review of Metastable Beta Titanium Alloys
(MDPI, 2018-06-30) Kolli, R. Prakash; Devaraj, Arun
In this article, we provide a broad and extensive review of beta titanium alloys. Beta titanium alloys are an important class of alloys that have found use in demanding applications such as aircraft structures and engines, and orthopedic and orthodontic implants. Their high strength, good corrosion resistance, excellent biocompatibility, and ease of fabrication provide significant advantages compared to other high performance alloys. The body-centered cubic (bcc) β-phase is metastable at temperatures below the beta transus temperature, providing these alloys with a wide range of microstructures and mechanical properties through processing and heat treatment. One attribute important for biomedical applications is the ability to adjust the modulus of elasticity through alloying and altering phase volume fractions. Furthermore, since these alloys are metastable, they experience stress-induced transformations in response to deformation. The attributes of these alloys make them the subject of many recent studies. In addition, researchers are pursuing development of new metastable and near-beta Ti alloys for advanced applications. In this article, we review several important topics of these alloys including phase stability, development history, thermo-mechanical processing and heat treatment, and stress-induced transformations. In addition, we address recent developments in new alloys, phase stability, superelasticity, and additive manufacturing.
A semi-supervised deep-learning approach for automatic crystal structure classification
(Wiley, 2022) Lolla, Satvik; Liang, Haotang; Kusne, A. Gilad; Takeuchi, Ichiro; Ratcliff, William
The structural solution problem can be a daunting and time-consuming task. Especially in the presence of impurity phases, current methods, such as indexing, become more unstable. In this work, the novel approach of semi-supervised learning is applied towards the problem of identifying the Bravais lattice and the space group of inorganic crystals. The reported semi-supervised generative deep-learning model can train on both labeled data, i.e. diffraction patterns with the associated crystal structure, and unlabeled data, i.e. diffraction patterns that lack this information. This approach allows the models to take advantage of the troves of unlabeled data that current supervised learning approaches cannot, which should result in models that can more accurately generalize to real data. In this work, powder diffraction patterns are classified into all 14 Bravais lattices and 144 space groups (the number is limited due to sparse coverage in crystal structure databases), which covers more crystal classes than other studies. The reported models also outperform current deep-learning approaches for both space group and Bravais lattice classification using fewer training data.
Additive Manufacturing of High-Temperature Hybrid Electronics via Molecular-Decomposed Metals
(Wiley, 2023-10-20) Khuje, Saurabh; Alshatnawi, Firas; Smilgies, Detlef; Alhendi, Mohammed; Islam, Abdullah; Armstrong, Jason; Yu, Jian; Poliks, Mark; Ren, Shenqiang
As the modern electronic technology extends into operating in harsh working conditions, it calls for a system that is capable of uncompromising performance in extreme environments, thus providing a strong motivation to look for advanced materials and electronics with the capability of high-throughput and rapid prototyping. Coupled with additive manufacturing, molecular decomposition metals bypass the challenging oddities of traditional material-limited and thermally initiated metalworking, enabling high throughput and rapid prototyping of stoichiometry and composition-controlled metals. Here, a new paradigm for the design and additive manufacturing of copper metallic alloy materials onto ceramics is described by printing molecular decomposable metal materials, capable of withstanding thermo-mechanical loading, operating in extreme environments in static and dynamic conditions. The resulting printed hybrid electronics are electrically stable for 25 h of aging at 1000 °C. This curious fact paves a way for printed antenna and sensor electronics that reliably operate up to 1000 °C. These results can be further extended to establish other printable molecular decomposable materials as a platform for rapid prototyping of high temperature electronics that are suitable for harsh environments.
Additive Manufacturing of High-Temperature Preceramic-Derived SiOC Hybrid Functional Ceramics
(Wiley, 2023-09-22) Li, Zheng; Khuje, Saurabh; Islam, Abdullah; Ren, Shenqiang
High-temperature capable materials, metals, and ceramics are attracting significant interest for applications in extreme environmental conditions. Herein, a hybrid metal-reinforced ceramic matrix material consisting of preceramic-derived high-temperature SiOC and copper nanoplates is reported, enabling the manufacturing of high-temperature sensing electronics. The preceramic polymer precursors including polydimethylsiloxane and polydimethylsilane, together with copper nanoplates, are thermally converted into durable copper-reinforced SiOC ceramics. The presence of copper in SiOC ceramics enhances its electrical conductivity, while SiOC suppresses oxygen uptake and acts as a shield for oxidation to achieve high-temperature thermal resistance and negative temperature coefficient at high temperatures. A comprehensive electric and sensing performance, combined with cost-effectiveness and scalability, can facilitate the utilization of hybrid Cu and SiOC composites in high-temperature electronics.
Cellulose Nanocomposites of Cellulose Nanofibers and Molecular Coils
(MDPI, 2021-07-30) Henderson, Doug; Zhang, Xin; Mao, Yimin; Hu, Liangbing; Briber, Robert M.; Wang, Howard
All-cellulose nanocomposites have been produced from cellulose nanofiber (CNF) suspensions and molecular coil solutions. Morphology and small-angle neutron scattering studies show the exfoliation and dispersion of CNFs in aqueous suspensions. Cellulose solutions in mixtures of ionic liquid and organic solvents were homogeneously mixed with CNF suspensions and subsequently dried to yield cellulose composites comprising CNF and amorphous cellulose over the entire composition range. Tensile tests show that stiffness and strength quantities of cellulose nanocomposites are the highest value at ca. 20% amorphous cellulose, while their fracture strain and toughness are the lowest. The inclusion of amorphous cellulose in cellulose nanocomposites alters their water uptake capacity, as measured in the ratio of the absorbed water to the cellulose mass, reducing from 37 for the neat CNF to less than 1 for a composite containing 35% or more amorphous cellulose. This study offers new insights into the design and production of all-cellulose nanocomposites.
Challenges of Overcoming Defects in Wide Bandgap Semiconductor Power Electronics
(MDPI, 2021-12-22) Setera, Brett; Christou, Aristos
The role of crystal defects in wide bandgap semiconductors and dielectrics under extreme environments (high temperature, high electric and magnetic fields, intense radiation, and mechanical stresses) found in power electronics is reviewed. Understanding defects requires real-time in situ material characterization during material synthesis and when the material is subjected to extreme environmental stress. Wide bandgap semiconductor devices are reviewed from the point of view of the role of defects and their impact on performance. It is shown that the reduction of defects represents a fundamental breakthrough that will enable wide bandgap (WBG) semiconductors to reach full potential. The main emphasis of the present review is to understand defect dynamics in WBG semiconductor bulk and at interfaces during the material synthesis and when subjected to extreme environments. High-brightness X-rays from synchrotron sources and advanced electron microscopy techniques are used for atomic-level material probing to understand and optimize the genesis and movement of crystal defects during material synthesis and extreme environmental stress. Strongly linked multi-scale modeling provides a deeper understanding of defect formation and defect dynamics in extreme environments.
Dataset for "Resistance of Boron Nitride Nanotubes to Radiation-Induced Oxidation" as published in The Journal of Physical Chemistry C
(2024) Chao, Hsin-Yun (Joy); Nolan, Adelaide M.; Hall, Alex T.; Golberg, Dmitri; Park, Cheol; Yang, Wei-Chang David; Mo, Yifei; Sharma, Renu; Cumings, John
Decomposition Mechanisms and Kinetics of Novel Energetic Molecules BNFF-1 and ANFF-1: Quantum-Chemical Modeling
(MDPI, 2013-07-18) Tsyshevsky, Roman V.; Kuklja, Maija M.
Decomposition mechanisms, activation barriers, Arrhenius parameters, and reaction kinetics of the novel explosive compounds, 3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (BNFF-1), and 3-(4-amino-1,2,5-oxadiazol-3-yl)-4-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole (ANFF-1) were explored by means of density functional theory with a range of functionals combined with variational transition state theory. BNFF-1 and ANFF-1 were recently suggested to be good candidates for insensitive high energy density materials. Our modeling reveals that the decomposition initiation in both BNFF-1 and ANFF-1 molecules is triggered by ring cleavage reactions while the further process is defined by a competition between two major pathways, the fast C-NO2 homolysis and slow nitro-nitrite isomerization releasing NO. We discuss insights on design of new energetic materials with targeted properties gained from our modeling.
Design principles for sodium superionic conductors
(Nature Portfolio, 2023-11-22) Wang, Shuo; Fu, Jiamin; Liu, Yunsheng; Saravanan, Ramanuja; Luo, Jing; Deng, Sixu; Sham, Tsun-Kong; Sun, Xueliang; Mo, Yifei
Motivated by the high-performance solid-state lithium batteries enabled by lithium superionic conductors, sodium superionic conductor materials have great potential to empower sodium batteries with high energy, low cost, and sustainability. A critical challenge lies in designing and discovering sodium superionic conductors with high ionic conductivities to enable the development of solid-state sodium batteries. Here, by studying the structures and diffusion mechanisms of Li-ion versus Na-ion conducting solids, we reveal the structural feature of face-sharing high-coordination sites for fast sodium-ion conductors. By applying this feature as a design principle, we discover a number of Na-ion conductors in oxides, sulfides, and halides. Notably, we discover a chloride-based family of Na-ion conductors NaxMyCl6 (M = La–Sm) with UCl3-type structure and experimentally validate with the highest reported ionic conductivity. Our findings not only pave the way for the future development of sodium-ion conductors for sodium batteries, but also consolidate design principles of fast ion-conducting materials for a variety of energy applications.
Direct and Rapid High-Temperature Upcycling of Degraded Graphite
(Wiley, 2023-06-27) Li, Tangyuan; Tao, Lei; Xu, Lin; Meng, Taotao; Clifford, Bryson Callie; Li, Shuke; Zhao, Xinpeng; Rao, Jiancun; Lin, Feng; Hu, Liangbing
Recycling the degraded graphite is becoming increasingly important, which can helped conserve natural resources, reduce waste, and provide economic and environmental benefits. However, current regeneration methods usually suffer from the use of harmful chemicals, high energy and time consumption, and poor scalability. Herein, we report a continuously high-temperature heating (≈2000 K) process to directly and rapidly upcycle degraded graphite containing impurities. A sloped carbon heater is designed to provide the continuous heating source, which enables robust control over the temperature profile, eliminating thermal barrier for heat transfer compared to conventional furnace heating. The upcycling process can be completed within 0.1 s when the degraded graphite rolls down the sloped heater, allowing us to produce the upcycled graphite on a large scale. High-temperature heating removes impurities and enhances the graphitization degree and (002) interlayer spacing, making the upcycled graphite more suitable for lithium intercalation and deintercalation. The assembled upcycled graphite||Li cell displays a high reversible capacity of ≈320 mAh g−1 at 1 C with a capacity retention of 96% after 500 cycles, comparable to current state-of-the-art recycled graphite. The method is a chemical-free, rapid, and scalable way to upcycle degraded graphite, and is adaptable to recycle other electrode materials.
Directed Kinetic Self-Assembly of Mounds on Patterned GaAs (001): Tunable Arrangement, Pattern Amplification and Self-Limiting Growth
(MDPI, 2014-05-12) Lin, Chuan-Fu; Kan, Hung-Chih; Kanakaraju, Subramaniam; Richardson, Christopher; Phaneuf, Raymond
We present results demonstrating directed self-assembly of nanometer-scale mounds during molecular beam epitaxial growth on patterned GaAs (001) surfaces. The mound arrangement is tunable via the growth temperature, with an inverse spacing or spatial frequency which can exceed that of the features of the template. We find that the range of film thickness over which particular mound arrangements persist is finite, due to an evolution of the shape of the mounds which causes their growth to self-limit. A difference in the film thickness at which mounds at different sites self-limit provides a means by which different arrangements can be produced.
Discrepancies and error evaluation metrics for machine learning interatomic potentials
(Springer Nature, 2023-09-26) Liu, Yunsheng; He, Xingfeng; Mo, Yifei
Machine learning interatomic potentials (MLIPs) are a promising technique for atomic modeling. While small errors are widely reported for MLIPs, an open concern is whether MLIPs can accurately reproduce atomistic dynamics and related physical properties in molecular dynamics (MD) simulations. In this study, we examine the state-of-the-art MLIPs and uncover several discrepancies related to atom dynamics, defects, and rare events (REs), compared to ab initio methods. We find that low averaged errors by current MLIP testing are insufficient, and develop quantitative metrics that better indicate the accurate prediction of atomic dynamics by MLIPs. The MLIPs optimized by the RE-based evaluation metrics are demonstrated to have improved prediction in multiple properties. The identified errors, the evaluation metrics, and the proposed process of developing such metrics are general to MLIPs, thus providing valuable guidance for future testing and improvements of accurate and reliable MLIPs for atomistic modeling.
Effect of Extended Extinction from Gold Nanopillar Arrays on the Absorbance Spectrum of a Bulk Heterojunction Organic Solar Cell
(MDPI, 2015-02-18) Tsai, Shu-Ju; Ballarotto, Mihaela; Kan, Hung-Chih; Phaneuf, Raymond J.
We report on the effects of enhanced absorption/scattering from arrays of Au nanopillars of varied size and spacing on the spectral response of a P3HT:PCBM bulk heterojunction solar cell. Nanopillar array-patterned devices do show increased optical extinction within a narrow range of wavelengths compared to control samples without such arrays. The measured external quantum efficiency and calculated absorbance, however, both show a decrease near the corresponding wavelengths. Numerical simulations indicate that for relatively narrow nanopillars, the increased optical extinction is dominated by absorption within the nanopillars, rather than scattering, and is likely dissipated by Joule heating.
Effect of Irradiation and Detection of Long-Lived Polyenyl Radicals in Highly Crystalline Ultra-High Molar Mass Polyethylene (UHMMPE) Fibers
(MDPI, 2019-05-27) Forster, Amanda L.; Tsinas, Zois; Al-Sheikhly, Mohamad
To improve properties such as thermal conductivity, low temperature thermal strain, and creep resistance of ultra-high molar mass polyethylene (UHMMPE) fibers, several researchers have previously undertaken efforts to crosslink these fibers using radiation. Ionizing radiation is commonly used to crosslink bulk UHMMPE in other applications, such as artificial joints. However, UHMMPE fibers differ from bulk UHMMPE in that they have a higher crystallinity (approximately 85% to 90%) and are very highly oriented during manufacturing in which the fibers are stretched 50 to 100 times their original length. Thus, the amorphous fraction of the UHMMPE fibers is also highly ordered. Several experiments were conducted to crosslink the UHMMPE fibers using both low dose rate (gamma) and high dose rate (electron beam) irradiation, all in the absence of oxygen. In all cases, the tensile strength of the fiber was greatly reduced by the irradiation. The oxidation index was also measured for the irradiated samples, and oxidation was not found to play a major role in the reduction of tensile strength in the fibers after irradiation. While this work did not achieve the desired result of improving the mechanical properties of the UHMMPE fiber, a significant result was found. The electron paramagnetic resonance (EPR) spectrum of the UHMMPE fibers was measured shortly after irradiation, and a mixture of allyl and alkyl radicals were detected. The irradiated samples were stored in dark ambient conditions for at least six years, then reexamined using EPR for free radical characterization. Surprisingly, the gamma-irradiated samples showed clear evidence of long-lived polyenyl radicals present in the material. Free radicals are very reactive species that will typically migrate to the surface of the crystalline domain and decay in a relatively short time through various reactions in the amorphous regions. It is hypothesized herein that due to the high crystallinity and large anisotropy of the highly drawn UHMMPE fiber, the polyenyl radicals were trapped in the crystal phase and were unable to migrate and decay. An experiment was performed to test this hypothesis, by which samples of the irradiated fibers were heated to temperatures above first the alpha relaxation and then melting point of polyethylene, and EPR measurements were taken. Results showed that the polyenyl radical signal persisted below the Tm, but was rapidly eliminated upon melting of the crystals. These experiments support the hypothesis that the long-lived polyenyl radicals are trapped in the crystalline region of the polyethylene fibers.
Flame retardant biogenic building insulation materials from hemp fiber
(Wiley, 2023-12-27) Jadhav, Porus Sunil; Sarkar, Arpita; Zhu, Long; Ren, Shenqiang
Biogenic thermal insulation materials are in high demand because of its carbon-sequestration nature. However, high flammability, moisture condensation, and relatively high thermal conductivity of biogenic material are major concerns for sustainable building applications. In this study, we report the fire-retardant cellulose xerogel insulation nanocomposites derived from hemp fiber recycling and silica xerogel, in which the boric acid treatment improves its fire retardancy. The as-prepared materials show a low thermal conductivity of 31.3 mW/m K, high flexural modulus of 665 MPa, hydrophobicity with the water contact angle of 115°, and fire retardancy with 30% weight loss over a period of burning time 10 min. Overall, this work provides an effective method for the synthesis of fire-retardant biogenic thermal insulation materials and shows a promising way for next-generation bio-based insulation materials.
Frustration in Super-Ionic Conductors Unraveled by the Density of Atomistic States
(Wiley, 2023-02-07) Wang, Shuo; Liu, Yunsheng; Mo, Yifei
The frustration in super-ionic conductors enables their exceptionally high ionic conductivities, which are desired for many technological applications including batteries and fuel cells. A key challenge in the study of frustration is the difficulties in analyzing a large number of disordered atomistic configurations. Using lithium super-ionic conductors as model systems, we propose and demonstrate the density of atomistic states (DOAS) analytics to quantitatively characterize the onset and degree of disordering, reveal the energetics of local disorder, and elucidate how the frustration enhances diffusion through the broadening and overlapping of the energy levels of atomistic states. Furthermore, material design strategies aided by the DOAS are devised and demonstrated for new super-ionic conductors. The DOAS is generally applicable analytics for unraveling fundamental mechanisms in complex atomistic systems and guiding material design.
High Sulfur Loading and Capacity Retention in Bilayer Garnet Sulfurized-Polyacrylonitrile/Lithium-Metal Batteries with Gel Polymer Electrolytes
(Wiley, 2023-09-24) Shi, Changmin; Takeuchi, Saya; Alexander, George V.; Hamann, Tanner; O'Neill, Jonathan; Dura, Joseph A.; Wachsman, Eric D.
The cubic-garnet (Li7La3Zr2O12, LLZO) lithium–sulfur battery shows great promise in the pursuit of achieving high energy densities. The sulfur used in the cathodes is abundant, inexpensive, and possesses high specific capacity. In addition, LLZO displays excellent chemical stability with Li metal; however, the instabilities in the sulfur cathode/LLZO interface can lead to performance degradation that limits the development of these batteries. Therefore, it is critical to resolve these interfacial challenges to achieve stable cycling. Here, an innovative gel polymer buffer layer to stabilize the sulfur cathode/LLZO interface is created. Employing a thin bilayer LLZO (dense/porous) architecture as a solid electrolyte and significantly high sulfur loading of 5.2 mg cm−2, stable cycling is achieved with a high initial discharge capacity of 1542 mAh g−1 (discharge current density of 0.87 mA cm−2) and an average discharge capacity of 1218 mAh g−1 (discharge current density of 1.74 mA cm−2) with 80% capacity retention over 265 cycles, at room temperature (22 °C) and without applied pressure. Achieving such stability with high sulfur loading is a major step in the development of potentially commercial garnet lithium–sulfur batteries.
High-Throughput Evaluation of Hardening Coefficients of Eight Alloying Elements in Magnesium
(Wiley, 2023-08-24) Wang, Chuangye; Zhong, Wei; Garnett, Jess; Zhao, Ji-Cheng
Liquid–solid diffusion couples (LSDCs) are employed to generate a composition gradient in the single-phase hexagonal closed-packed (hcp) solid solution with compositions up to the solubility limit of various solutes in Mg. Nanoindentation scanning across the composition gradient in LSDCs allows effective evaluation of composition-dependent hardness of eight alloying elements (Al, Ca, Ce, Gd, Li, Sn, Y, and Zn) in the hcp Mg phase. The hardening coefficients, an indicator of the potency of solid-solution hardening, are evaluated from the measured composition-hardness data and correlated with various materials properties such as atomic radius, shear modulus, and elastic modulus of the solutes. The rank of hardening potency of Al, Gd, Sn, Y, and Zn measured by nanoindentation is in good agreement with that measured by microindentation reported in the literature. The hardening coefficient (potency) from the strongest to the weakest is Ce > Ca > Y ≈ Gd > Zn > Al ≈ Sn > Li in Mg-based hcp binary solid solutions. The hardening coefficient is found to be closely correlated with the strengthening potency.
Interface Diagnostics Platform for Thin-Film Solid-State Batteries
(2024-08-28) Ferrari, Victoria Castagna; Stewart, David Murdock; Rubloff, Gary
This dataset comprises electorchemical impedance spectroscopy measurements from thin film batteries comprised of LiV2O5, LiPON, and Si. The data is associated with a manuscript that describes the methodology and analysis of the data and conclusions we draw from it in complete detail. (At the time of submission, the manuscript was set to be submitted to a peer reviewed journal.) The data herein is intended to be used to model equivalent circuits for each material and the charge transfer interfaces throughout the device in order to construct the model of the full battery. The demonstrated methods to build from simple materials to a complex device are novel in the field and we hope this data and process will be used by other researchers to develop more robust analysis of batteries across academic labs and industry.