2020 Undergraduate Student Poster Contest: 2020 Undergraduate Student Poster Contest
Program Organizers: Yolanda Natividad, American Ceramic Society
Tuesday 12:00 PM
November 3, 2020
Room: Poster Hall
Location: MS&T Virtual
Additive Manufacturing of Titanium-based Functionally Graded Materials: Experiment Characterization and FEA Modeling: Yang Liu1; 1WHUT
Functionally graded materials (FGMs) are a class of material systems with properties that vary over one or more dimension by progressively changing the chemistry or microstructure with position. One method for fabricating FGMs with varying elemental composition is through layer-by-layer directed energy deposition additive manufacturing (AM). The capacity to create multi-phase materials with gradual variations in compositions and structures defined as functionally graded additive manufacturing (FGAM). Titanium-based FGMs have high strength-to-weight ratio, excellent biocompatibility, thus they can be applied in aerospace and medical field. However, the challenge for FGMs fabricated by AM is the delamination of the part caused by intermediate phases. By elaborating on additive manufacturing (AM) processes, structure and properties, we provide a detailed guideline for the design of the Titanium-based FGMs. The experimental-computational approach described herein for characterizing FGMs can be used to improve the understanding and design of other FGMs.
Alloying MnGeTe2 Enables High Thermoelectric Performance: Grace Rome1; 1Colorado School of Mines
Thermoelectric materials convert thermal gradients into electricity. They’re currently used in space applications to provide power, but they also have the potential to be used to increase energy efficiency by harnessing waste heat. However, to reach the point of wide-spread application, the efficiency of thermoelectric materials must be increased. This work investigates MnGeTe2, a high performing thermoelectric material. Doping/alloying was used in order to obtain a better understanding of the electronic properties by adjusting the carrier concentrations of the materials. The samples were tested for their structural and electrical properties and compared to literature. Bismuth doping was found to improve the thermoelectric figure of merit (zT) in comparison to literature values within the same composition space. Our findings also indicate that the material retains a cubic structure across a large composition space, indicating that there are opportunities for significant improvements of thermoelectric performance.
Analysis of High Entropy Ceramics Prepared via Steric Entrapment and Solid-state Sintering Methods: Crystal Structure: Madeline Loveday1; Matheus Pianassola1; Merry Koschan1; Charles Melcher1; Mariya Zhuravleva1; 1University of Tennessee, Knoxville
This project was designed to evaluate phase formation of high-entropy ceramics made via one of two synthesis methods: solid-state sintering or steric entrapment. Powder x-ray diffraction was used for phase identification. The compositions studied are five-component rare-earth aluminum garnets or perovskites with the general formula RE3Al5O12 and REAlO3, respectively, where RE represents an equiatomic combination of five rare-earth elements. Three combinations were selected for study: (Lu, Yb, Y, Tb, Gd), (Lu, Yb, Y, Tb, Eu), and (Lu, Yb, Y, Eu, Nd). Parameters such as crystallization temperature and PVA dissolution methods were studied to optimize steric entrapment for these materials. The results of this research will be used to inform future precursor synthesis parameters for use in future crystal growth via the micro-pulling down method.
Comparative Study of Transport propeties of Bismuth Sulfide with Different Dopants: Farheen Anjum1; 1IIT Kanpur
A large band gap and hence low electrical conductivity in comparison to other bismuth chalcogenides limits thermoelectric performance bismuth sulfide. Various strategies such as doping have been used for improving its TE performance. Here we report the synthesis and thermoelectric properties of SPSed Bi2S3 and enhanced its performance by using x-mole% of CuCl2 , x-mole% CaCl2 ,SnS2 as dopant. Powder in stoichiometric compositions were mixed and synthesised by melt and grow process and sintered by SPS. XRD of all samples shows single phase formation. The increasing halide dopant concentration leads to the improvement in its electrical property and after an optimised value it decreases. As a result a higher power factor ~2000 μW/m-K2 for CuCl2 as dopant and ~1600 μW/m-K2 for CaCl2 is obtained. However sulphide dopant deceases conductivity as well as PF very low. ZT values greater than 1 was achieved in these halide doped chalcogenides.
Crack Driving Force Expressions Using Compliance Approach in Clamped Beam Bending Geometry: Tejas Chaudhari1; Ashwini Mishra1; Hrushikesh Sahasrabuddhe1; Nagamani Jaya Balila1; 1IIT Bombay
The geometric stability for controlled crack growth is shown, and stress intensity factor solutions are derived in single edge-notched clamped beam specimens (SENCB) in the previous work. In the present study, numerical simulations are carried out through an extended finite element method (XFEM) to derive crack driving force solutions for different beam aspect ratios (L/W) and elastic moduli (E). In the case of linear elastic fracture mechanics (LEFM), the crack driving force is also known as the energy release rate (G). The expressions for G are derived using an energy-based compliance approach, which is more convenient to execute in a realistic scenario. The variations in G with crack length (a) through the compliance approach are compared with those obtained directly from XFEM. Experimental validation of the G obtained has also been carried out at the macro-scale using a linear elastic material poly-methyl methacrylate (PMMA).
Crystal Structure and Lithium Ionic Transport Behavior of Li Site Doped Li7La3Zr2O12: Qianshun Cui1; 1Wuhan University of Technology
To stabilize Li7La3Zr2O12（LLZO） as cubic phase and improve Li+ conductivity, doping some elements on Li site is an effective method, and the reported possible Li site elements calculated by first principle are Be, B, Al, Fe, Zn, Ga. And the Ga-doped LLZO shows a higher conductivity than other LLZO. However, it remains to be further verified whether all these elements can stable LLZO as cubic phase and why Ga exhibits higher conductivity. In this work, these elements were tried to be dopped on Li site and the results show that only the Al, or Fe, or Ga can stable LLZO as cubic phase among these elements. Besides, the Ga-doped LLZO with the highest conductivity were fabricated, whose outstanding conductivity can be attributed to the transform of group space from Ia-3d to I-43d, shorter distances between different Li+, and the improved grain size created by Ga.
Developing Materials and Coating Technologies for Mitigation of Lunar Dust Adhesion and Abrasion: Dylan Lew1; Nicolas Fransen2; Valerie Wiesner3; Christopher Wohl3; Lopamudra Das4; 1Carnegie Mellon University; 2Purdue University; 3NASA Langley Research Center; 4National Institute of Aerospace
In order to enable long duration missions to the lunar surface, materials resistant to the harsh lunar environment are critically needed. Lunar dust poses a significant threat to the durability of components and vehicles operating on the lunar surface. The fine, jagged morphology and highly abrasive nature of the dust enable particles to adhere and embed into surfaces of components and devices potentially leading to premature failure.The objective of this project is to examine properties of candidate ceramic material systems that are highly wear resistant and/or resistant to lunar dust adhesion for lunar applications as coatings and/or bulk components. This project supports the Lunar Dust Patch Plate Experiment that is currently scheduled to launch in fiscal year 2022 to enable real environment evaluation of candidate materials for Lunar exploration applications.
Development of a Blast Furnace Simulator: Adam Binder1; Nicholas Rheinheimer1; 1Purdue University Northwest
In a blast furnace, hot pressurized air is forced into a packed bed of coke to create heat and reducing gases for turning iron ore into liquid iron. Currently, operators generally rely on rules of thumb to estimate the response of the furnace to changing conditions. Given high operating costs involved, it is often impractical to study these impacts in the field. The complexity of the process means that optimization can be difficult, and misguided attempts can increase costs and causing stability issues. The project objective is to develop a software capable of using pre-generated computational fluid dynamics (CFD) data detailing the blast furnace internal state under different operating conditions to quickly predict the impacts on blast furnace performance. Using this data, interpolation and curve-fitting will be applied to predict furnace operation under conditions not previously calculated. Additionally, a web-based GUI will be developed to enhance ease-of-use.
Effect of Aspect Ratio on Stress Intensity Factor Solutions for Single Edge Notch Wire Fracture Test Specimen under Tensile and Clamped Bend Loading Conditions: Hrushikesh Sahasrabuddhe1; Ashwini Mishra1; Nagamani Jaya Balila1; 1India Institute of Technology Bombay
Finite element analysis has been employed to evaluate the stress intensity factors ahead of a straight fronted surface crack in a cylindrical rod specimen in tension & clamped bend loading. Closed form 3-dimensional as well as 2-dimensional stress intensity factor solutions have been derived in terms of the relative crack depth, wire aspect ratio as alternatives to existing solutions. Our study establishes the strong influence of wire aspect ratio on the geometric factor which were ignored in the studies carried out earlier. Experimental validation of the geometric factor solutions is obtained by testing them against a brittle linear elastic polymeric material - PMMA, with a known mode 1 notch toughness (K1Q). The results are explained in terms of the stress state ahead of such an asymmetric notch and the boundary conditions that result out of the loading constraints under tension and clamped bending.
Efficient and Stable Perovskite Solar Cells via Surface Passivation of an Ultrathin Hydrophobic Organic Molecular Layer: Xiaofeng Gao1; 1Wuhan University of Technology
Organic and inorganic metal halide perovskite solar cells (PSCs) have been regarded as the next-generation photovoltaic technology. However, the solution processed perovskite films usually have abundant defects, especially at the grain boundaries and surfaces, causing some disadvantages. Herein, 4-(trifluoromethyl)benzylamine (TFMBA) is deposited on the surface of perovskites to form an ultrathin hydrophobic organic molecular layer, passivating the interfacial imperfections. By optimizing the post-treatment conditions, a remarkable power conversion efficiency (PCE) of 20.56% is realized. Impressively, the passivated ultrathin organic molecular layer effectively prohibits the penetration of moisture, resulting in unsealed PSCs retaining 84% of the original PCE after aged 1300 h at 65%−75% relative humidity (RH). SEM and XRD confirm that TFMBA can effectively passivate defects on the surface and grain boundaries, thereby prevent the perovskites from the irreversible decomposition with the immersion of moisture. This suggests that the TFMBA post-treatment contributes to high-quality and stable perovskite films.
Innovative Preparation Methods of High Performance Magnetically Responsive Photonic Crystals: Linxin Huang1; 1Wuhan University of Technology
Magnetically responsive photonic crystals self-assemble into crystalline colloidal arrays with the lattice constant adjustable by H. However, they have not been widely used in sensors, color displays and optical camouflage because of their slow response and limited tunability of photonic bandgap. For the first time, we have synthesized monodisperse super-paramagneyic particles by a modified polyol process in the presence of glucose and poly. They show a long-range steric repulsion sufficiently strong to counteract the magnetic attractive force. We then constructed steric repulsion-stabilized MRPCs in diverse organic solvents. The as-built MRPCs in solvents compatible well with PVP show color tunability nearly within the entire visible spectrum and almost independent of the solvent polarity, ionic strength, or pH value, highlighting the advantages for the preparation of polymer-matrix PC composites.
Maximizing Magnetostriction in Fe-Ga-Zr Nanocrystalline Alloys: Ria Nandwana1; Matthew Willard1; Yumi Ijiri2; 1Case Western Reserve University; 2Oberlin College
There is a demand for materials with large magnetostrictive coefficients due to their applicability in tunable multiferroic sensors. Fe-Ga single crystals and polycrystalline materials have exhibited large magnetostrictive coefficients on the order of several hundred ppm in bulk samples. Nanocrystalline Fe-Ga alloys would be advantageous for these sensor applications; however, they have been found to exhibit lower magnetostrictive coefficients. In our experiments, (Fe100-xGax)92Zr8 alloys were synthesized in the form of nanocomposite ribbons by rapid solidification processing. X-ray diffraction measurements were taken before and after annealing to ensure that the desired crystal structure was achieved. When measured, a maximum magnetostriction of 10.4 ppm was found at x= 22 for the nanocomposite ribbons. The coercivity and saturation magnetization of the sample was measured using VSM for additional characterization.
Nanocrystalline Magnetic Metallic Microwave Absorbents Working at Elevated Temperature: Shuaiwei Guo1; 1Wuhan University of Technology
Nanocrystalline magnetic metallic microwave absorbents have been widely used to produce microwave absorbing coatings of thin thickness and low density, since they can simultaneously cause magnetic and dielectric loss to microwave. However, when nanocrystalline magnetic metallic absorbents work at elevated temperature, they generally suffer from three challenges, i.e., increase in amplitude for atomic dynamic vibration, oxidation and grain growth. This work aims to provide systematic understanding to challenges and strategies for magnetic absorbent working at high temperature, focusing on the origination, mechanism and effect of Curie temperature, high temperature oxidation and grain growth. The strategies to suppress disordering magnetic moments, oxidation and grain coarsening are discussed from the perspectives of alloying art and nanostructure controlling; surface coating, formation of dense metal oxide layer to suppress oxygen diffusion and internal structure construction; thermodynamics, kinetics and thermodynamic-kinetic synergy, respectively. This work is constructive to promote high-temperature application of magnetic metallic absorbents.
Origin of the Phase Transition in Lithium Garnets: Lu Xinqi1; 1Functionally Graded Materials
In order to obtain a better understanding of the origin of phase transition in garnet-type Li7La3Zr2O12 solid electrolyte, we perform Molecular dynamic and density functional theory based simulations. With the investigation of lithium distribution and dynamics, we found one temperature-dependent lithium migration pathway in lithium garnets. Lithium ions exhibited uniformly 3-dimensional diffusion in cubic LLZO, but the lithium diffusion in tetragonal LLZO was mainly in the a and b direction. The constrained diffusion in the c direction in tetragonal LLZO could be ascribed to the blocking effect of 16f sites which were found to be thermodynamically more stable than tetragonal 8a and 32g sites through density functional theory based calculations.
Quantitatively Accounting for the Effects of Surface Topography on the Oxidation Kinetics of Additive Manufactured Hastelloy X Processed by Electron Beam Melting: Matthew Kuner1; Marie Romedenne2; Patxi Fernandez-Zelaia2; Sebastien Dryepondt2; 1Georgia Institute of Technology; 2Oak Ridge National Laboratory
The effects of surface roughness on the high-temperature corrosion of nickel-based superalloy X produced through electron-beam melting (EBM) additive manufacturing were studied. Surface area of samples in the rough, as-fabricated condition was measured using a 2D cross-section image analysis technique and a 3D image analysis technique. To evaluate the accuracy of surface area measurements, oxidation testing of samples in the as-fabricated and polished conditions was performed. Polished sample oxidation curves were then compared to the as-fabricated sample oxidation curves before and after being adjusted using obtained surface area measurements. It was found that the 2D technique accurately measured surface area and accounted for the overlapping features present on EBM sample surfaces, whereas the 3D technique did not.
Supercritical Synthesis of VO2 Nanoparticles For Smart Window Films: Robert Spurling1; Elizabeth Rasmussen1; Mai Tran1; Jie Li1; 1Argonne National Laboratory
VO2 nanoparticles have attracted significant research interest for energy-saving smart window applications due to their ability to selectively block infrared heat while transmitting visible light. These VO2 nanoparticles are synthesized using a continuous-flow hydrothermal mixing reactor which must operate at supercritical conditions. However, experimental results have indicated that the optical properties of the as-synthesized VO2 nanoparticles are dependent upon the dimensions and relative uniformity of nanoparticle sizes, which are in turn a product of the degree of mixing during synthesis. Therefore, this current work leverages computer simulations to determine the optimum reactor design and boundary conditions which are most conducive to uniform mixing during nanoparticle synthesis. Initial results indicate that, given the current reactor design and operating parameters, the VO2 nanoparticles do not undergo uniform quenching, which could give rise to non-uniform nanoparticle sizes and inconsistent optical properties.
Unique S-scheme Heterojunctions in Self-assembled TiO2/CsPbBr3 Hybrids for CO2 Photoreduction: Kai Meng1; 1Wuhan University of Technology
Exploring photocatalysts to promote CO2 photoreduction into solar fuels is of great significance. We develop TiO2/perovskite (CsPbBr3) S-scheme heterojunctions synthesized by a facile electrostatic-driven self-assembling approach. Density functional theory calculation combined with experimental studies proves the electron transfer from CsPbBr3 quantum dots (QDs) to TiO2, resulting in the construction of internal electric field (IEF) directing from CsPbBr3 to TiO2 upon hybridization. The IEF drives the photoexcited electrons in TiO2 to CsPbBr3 upon light irradiation as revealed by in-situ X-ray photoelectron spectroscopy analysis, suggesting the formation of an S-scheme heterojunction in the TiO2/CsPbBr3 nanohybrids which greatly promotes the separation of electron-hole pairs to foster efficient CO2 photoreduction. The hybrid nanofibers unveil a higher CO2-reduction rate (9.02 μmol g–1 h–1) comparing with pristine TiO2 nanofibers (4.68 μmol g–1 h–1). Isotope (13CO2) tracer results confirm that the reduction products originate from CO2 source.