Materials Science and Engineering Commons^™

Thermal And Electrical Properties Of Spark Plasma Sintered (Ti,Cr)B2 Ceramics, Steven M. Smith, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Laura Silvestroni

Mathematics and Statistics Faculty Research & Creative Works

Thermal and electrical properties were measured for TiB2 ceramics containing varying CrB2 contents up to 33 mol%. The room-temperature thermal diffusivity decreased with increasing Cr content from 0.330 ± 0.003 cm2/s for pure TiB2 to 0.060 ± 0.003 cm2/s for (Ti0.66Cr0.33)B2. The amount of anisotropy in the coefficients of thermal expansion increased with increasing Cr content and the c-axis had the greatest dependence on Cr addition, with an increase of more than 25% in the thermal expansion for 33 mol% CrB2 compared to TiB2, whereas the a-axis only increased by about 8%. The electrical conductivity was the lowest for (Ti0.66Cr0.33)B2 …

A Deep Learning-Informed Design Scheme For Shear Friction At Concrete-To-Concrete Interface: Recommendations For Inclusion In Aashto Lrfd Guidelines, Tarutal Ghosh Mondal, Nikkolas Edgmond, Lesley Sneed, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Recent advancements in construction technology have led to high-strength concrete and steel. However, these developments have depreciated the accuracy of the design equations in current provisions, which were based on normal-grade materials. To fill such a research gap, this study presents a novel deep learning-based computation scheme that can replace the current design provisions by virtue of its superior accuracy and reliability. The proposed approach exploits Neural Additive Models (NAMs) in which geometric and material properties associated with a normal weight concrete-to-concrete shear interface are inputted to individual neural network blocks. The outputs of the individual blocks are linearly combined …

Cascaded Sapphire Fiber Bragg Gratings Inscribed By Femtosecond Laser For Molten Steel Studies, Dinesh Reddy Alla, Deva Prasad Neelakandan, Farhan Mumtaz, Rex E. Gerald, Laura Bartlett, Ronald J. O'Malley, Jeffrey D. Smith, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This research reports a distributed fiber optic high-temperature sensing system tailored for applications in the steel industry and various other sectors. Recent advancements in optical sensor technology have led to the exploration of sapphire crystal fibers as a solution for sensing in harsh environments. Utilizing a femtosecond (fs) laser, cascaded fiber Bragg gratings (FBGs) were meticulously fabricated within a multimode sapphire optical fiber. These FBGs endowed the system with distributed sensing capabilities and underwent rigorous testing under extreme temperatures, reaching up to 1,800 °C. The study delves into the investigation of the FBG reflection spectrum, facilitated by the development of …

Predicting Dissolution Kinetics Of Tricalcium Silicate Using Deep Learning And Analytical Models, Taihao Han, Sai Akshay Ponduru, Arianit Reka, Jie Huang, Gaurav Sant, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

The dissolution kinetics of Portland cement is a critical factor in controlling the hydration reaction and improving the performance of concrete. Tricalcium silicate (C₃S), the primary phase in Portland cement, is known to have complex dissolution mechanisms that involve multiple reactions and changes to particle surfaces. As a result, current analytical models are unable to accurately predict the dissolution kinetics of C₃S in various solvents when it is undersaturated with respect to the solvent. This paper employs the deep forest (DF) model to predict the dissolution rate of C₃S in the undersaturated solvent. The …

Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Calcium aluminate cement (CAC) has been explored as a sustainable alternative to Portland cement, the most widely used type of cement. However, the hydration reaction and mechanical properties of CAC can be influenced by various factors such as water content, Li₂CO₃ content, and age. Due to the complex interactions between the precursors in CAC, traditional analytical models have struggled to predict CAC binders' compressive strength and porosity accurately. To overcome this limitation, this study utilizes machine learning (ML) to predict the properties of CAC. The study begins by using thermodynamic simulations to determine the phase assemblages of …

Deep Reinforcement Learning For Approximate Policy Iteration: Convergence Analysis And A Post-Earthquake Disaster Response Case Study, Abhijit Gosavi, L. (Lesley) H. Sneed, L. A. Spearing

Engineering Management and Systems Engineering Faculty Research & Creative Works

Approximate Policy Iteration (API) is a Class of Reinforcement Learning (RL) Algorithms that Seek to Solve the Long-Run Discounted Reward Markov Decision Process (MDP), Via the Policy Iteration Paradigm, Without Learning the Transition Model in the Underlying Bellman Equation. Unfortunately, These Algorithms Suffer from a Defect Known as Chattering in Which the Solution (Policy) Delivered in Each Iteration of the Algorithm Oscillates between Improved and Worsened Policies, Leading to Sub-Optimal Behavior. Two Causes for This that Have Been Traced to the Crucial Policy Improvement Step Are: (I) the Inaccuracies in the Policy Improvement Function and (Ii) the Exploration/exploitation Tradeoff Integral …

Suppressing Aluminum/Silica Exchange Reaction Between High Aluminum Steel And Mold Flux During Continuous Casting Process, Kuanysh Nurbekuly Yermukhanbetov

Masters Theses

"Mold flux plays one of the critical roles in continuous casting of steel. It performs five primary functions: thermal and chemical insulation, lubrication between the steel strand and mold, absorption of inclusions, and promotion of even heat flux. The aluminum/silica exchange reaction occurring between steel and mold flux during the continuous casting process poses significant challenges in the steel industry. This reaction can lead to various defects in the cast product and adversely affect its surface quality, as well as downstream processing.

In this work, effectiveness of two approaches, namely slag dopant additions and electrochemical techniques, in suppressing the exchange …

Development And Testing Of A Hyperbaric Aerodynamic Levitator For Containerless Materials Research, Sydney Elizabeth Boland

Masters Theses

"This research focused on the development and testing of a hyperbaric aerodynamic levitator for container less materials research of specimens at temperatures greater than 2000°C and pressures up to 10.3 MPa (1500 psi). The effect of specimen size, specimen density, pressure, and flow rate on the levitation behavior was studied. Lightweight specimens demonstrated two stable levitation regimes that were speculated to be associated with a change in the turbulent wake structure. The hyperbaric aerodynamic levitator was also used to determine the effect of pressure on the heat transfer by studying the melting behavior of a levitated 3.0 mm diameter alumina …

Phosphate And Borophosphate Glasses For Optical And Biomedical Applications, Parker Tracy Freudenberger

Doctoral Dissertations

"The goal of this work was to connect the network structures of phosphate and borophosphate glasses to the compositional dependence of properties related to biomedical applications. The glasses were characterized by a variety of techniques, including phosphate ion chromatography, Raman spectroscopy, and ¹¹B and ³¹P Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy, which provide qualitative and quantitative information about the phosphate and borate moieties that constitute the network structures. The systematic addition of borate to a phosphate glass initially creates tetrahedral borate sites that replace P-O-P linkages with B-O-P linkages, and the properties of the resulting borophosphate glasses …

Intragranular Tungsten-Titanium Carbide Composite Ceramics Via Gas-Solid Displacement Reactions, Ryan Daniel Dempsey

Doctoral Dissertations

"Research presented herein details the synthesis and characterization of nanocomposite ceramics featuring novel heterogeneous microstructures of potential interest in a variety of electrical and structural applications. Specifically, W-TiCy composite ceramics featuring tungsten nanoprecipitates located primarily within TiCy grains have been produced via sintering of intragranular nanocomposite powders produced via reaction processing-based techniques. This dissertation details the thermodynamic basis and applied kinetics of a processing scheme for fabricating nanocomposite ceramics whose morphological heterogeneity reflects that originally developed in the powder state. The first study in this series overviews the motivation for applying metallothermic displacement reactions, conducted through gaseous intermediates, to solid …

A Fiber-Optic Sensor-Embedded And Machine Learning Assisted Smart Helmet For Multi-Variable Blunt Force Impact Sensing In Real Time, Yiyang Zhuang, Taihao Han, Qingbo Yang, Ryan O'Malley, Aditya Kumar, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

Early on-site diagnosis of mild traumatic brain injury (mTBI) will provide the best guidance for clinical practice. However, existing methods and sensors cannot provide sufficiently detailed physical information related to the blunt force impact. In the present work, a smart helmet with a single embedded fiber Bragg grating (FBG) sensor is developed, which can monitor complex blunt force impact events in real time under both wired and wireless modes. The transient oscillatory signal "fingerprint" can specifically reflect the impact-caused physical deformation of the local helmet structure. By combination with machine learning algorithms, the unknown transient impact can be recognized quickly …

Local Structure In High-Entropy Transition Metal Diborides, Mattia Gaboardi, Frederic Monteverde, Federico Saraga, Giuliana Aquilanti, Lun Feng, William Fahrenholtz, Gregory Hilmas

Materials Science and Engineering Faculty Research & Creative Works

Studies on high-entropy materials often speculate about the effects of lattice distortion and disorder on characteristics such as hardness, thermal expansion, and electronic properties. Notwithstanding the ongoing race to discover new compositions, investigations of the local structure at the atomic level remain sparse at best. Additionally, assessments of the homogeneity of the distribution of metals within the lattice sites are often restricted to techniques such as energy dispersive spectroscopy which might lead to an inaccurate picture of the bulk material. Herein, we report an extensive and systematic study of a class of emerging high-entropy ceramics that uses a combination of …

Hanford Low-Activity Waste Glass Composition-Temperature-Melt Viscosity Relationships, Alejandro Heredia-Langner, Vivianaluxa Gervasio, Scott K. Cooley, Charmayne E. Lonergan, Dong Sang Kim, Albert A. Kruger, John D. Vienna

Materials Science and Engineering Faculty Research & Creative Works

This study developed a model for predicting viscosity of alkali-alumino-borosilicate glass melts as functions of composition and temperature. The model is based on a total of 3935 viscosity-temperature data from 574 glasses with viscosity values ranging from 2.53 to 7260 Poise (P) in the temperature range of 900–1260°C. Several different model forms were surveyed, including those based on Arrhenius, Vogel-Fulcher-Tammann, Avramov-Milchev, and Mauro-Yue-Ellison-Gupta-Allen. For each of these models, combinations of the temperature-independent parameters were fitted to composition. It was found that generally fitting more than one temperature-independent parameter as functions of composition resulted in overfitting. The Avramov-Milchev-based model was found …

Effect Of Cu Additions On Scale Structure And Descaling Efficiency Of Low C Steel Reheated In A Combustion Gas Atmosphere, Richard Osei, Simon Lekakh, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Modern EAF steelmaking employs scrap as its primary source of raw material. Different sources of scrap have varying levels of residuals, which can negatively influence product properties, performance, and surface quality. The presence of some residuals, such as Cu and Ni in controlled quantities, can also positively impact steel performance for some applications. It is also well known that interactions between residuals and alloying elements in steel can modify the structure of scale formed during slab reheating prior to hot rolling. These changes in the scale structure can influence scale removability. In this study, the effect of varying Cu concentrations …

Fusion Welding Of Refractory Metals And Zrb2-Sic-Zrc Ceramics, Jecee D. Jarman, William Fahrenholtz, Greg Hilmas, Jeremy Lee Watts, Tieshu Huang

Materials Science and Engineering Faculty Research & Creative Works

Molybdenum and a molybdenum alloy were fusion welded to ZrB2-based ceramics to determine if the electrical and thermal properties of the metals and ceramics affected their weldability. Commercial ceramic powders were hot pressed, machined into coupons, and preheated to 1600 °C before joining the ceramics to commercial metals using plasma arc welding. Weldability varied as indicated by the range of porosity observed within the fusion zones. Measured thermal and electrical properties appeared to have little to no effect on the weldability of metal-ceramic welds despite the large range of values measured across each property. Differences in melting temperatures between metal …

Stochastic Model For High Temperature Oxidation Of Cr–Ni Austenitic Steels Assisted By Spallation, Simon N. Lekakh, Oleg Neroslavsky, Mei Li, Larry Godlevski

Materials Science and Engineering Faculty Research & Creative Works

Cr–Ni austenitic steels offer significant high temperature corrosion protection by forming a surface oxide layer. However, above critical service conditions (temperature, atmosphere, thermal cycling), oxidized surface can experience intensive degradation because of scale spallation, which could be detrimental to the in-service life. To predict the effect of scale spallation on oxidation kinetics, a simulation was implemented using a stochastic model. The model considers topological parameters and intensity of spallation which can occur, while delivering a true oxidation constant. The experimental procedure identified the amount of formed spalled scale and topology of spallation based on the use of element mapping of …

Additive Manufacturing Of Complexly Shaped Sic With High Density Via Extrusion-Based Technique – Effects Of Slurry Thixotropic Behavior And 3d Printing Parameters, Ruoyu Chen, Adam Bratten, Joshua Rittenhouse, Tian Huang, Wenbao Jia, Ming-Chuan Leu, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing of dense SiC parts was achieved via an extrusion-based process followed by electrical-field assisted pressure-less sintering. The aim of this research was to study the effect of the rheological behavior of SiC slurry on the printing process and quality, as well as the influence of 3D printing parameters on the dimensions of the extruded filament, which are directly related to the printing precision and quality. Different solid contents and dispersant- Darvan 821A concentrations were studied to optimize the viscosity, thixotropy and sedimentation rate of the slurry. The optimal slurry was composed of 77.5 wt% SiC, Y2O3 and Al2O3 …

Study Of Asymptotic Velocity In The Bondi–Hoyle Accretion Flows In The Domain Of Kerr And 4-D Einstein–Gauss–Bonnet Gravities, Orhan Donmez, Fatih Dogan, Tuba Sahin

Materials Science and Engineering Faculty Research & Creative Works

Understanding the physical structures of the accreted matter very close to a black hole in quasars and active galactic nucleus (AGN) is an important milestone to constrain the activities occurring in their centers. In this paper, we numerically investigate the effects of the asymptotic velocities on the physical structures of the accretion disk around the Kerr and Einstein–Gauss–Bonnet (EGB) rapidly rotating black holes. The Bondi–Hoyle accretion is considered with a falling gas towards the black hole in an upstream region of the computational domain. Shock cones are naturally formed in the downstream part of the flow around both black holes. …

Global Tellurium Supply Potential From Electrolytic Copper Refining, Nedal T. Nassar, Haeyeon Kim, Max Frenzel, Michael S. Moats, Sarah M. Hayes

Materials Science and Engineering Faculty Research & Creative Works

The transition towards renewable energy requires increasing quantities of nonfuel mineral commodities, including tellurium used in certain photovoltaics. While demand for tellurium may increase markedly, the potential to increase tellurium supply is not well-understood. In this analysis, we estimate the quantity of tellurium contained in anode slimes generated by electrolytic copper refining by country between 1986 and 2018, including uncertainties. For 2018, the results indicate that 1930 (1500-2700, 95% confidence interval) metric tons of tellurium were contained in anode slimes globally. This is nearly quadruple the reported tellurium production for that year. China has the greatest potential to increase tellurium …

High-Entropy Boride–Carbide Ceramics By Sequential Boro/Carbothermal Synthesis, Steven M. Smith, Lun Feng, William Fahrenholtz, Greg Hilmas, Tieshu Huang

Materials Science and Engineering Faculty Research & Creative Works

A dual-phase high-entropy boride (HEB)/carbide (HEC) ceramic with a fine grain size was synthesized by a sequential boro/carbothermal process. In the first step, an Hf–Nb–Ta–Ti–Zr-containing carbide was synthesized by a carbothermal reduction of oxides followed by the reaction of the carbide with B4C and ZrH2 to convert part of the carbide to boride. The resulting composition was ∼29 vol% HEB with an average grain size of ∼1.1 μm. Solid solution formation occurred at the densification temperature of 1900°C resulting in a relative density higher than 99%. The Vickers hardness was 26.5 ± 1.4 GPa. This is the first report of …

Improved Additive Manufacturing Of Silicon Carbide Parts Via Pressureless Electric Field-Assisted Sintering, Adam Bratten, Ruoyu Chen, Joshua Rittenhouse, Ming-Chuan Leu, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

High solids loading silicon carbide (SiC)-based aqueous slurries containing only.5 wt. % organic additives were utilized to create specimens of various geometries via an extrusion-based additive manufacturing (AM) technique. Pressure less electric field-assisted sintering was performed to densify each specimen without deformation. The combination of these techniques produced parts with >98% relative density despite containing only 5 wt.% oxide sintering additives. After sintering, specimens contained only the α-SiC and yttrium aluminum perovskite phases. This suggests the evolution of a nonequilibrium yttrium aluminate phase, as well as transformation from β-SiC to α-SiC. The fabrication method presented in this work has advantages …

Effect Of Rolling Process On Magnetic Properties Of Fe-3.3 Wt% Si Non-Oriented Electrical Steel, Yizhou Du, Ronald J. O'Malley, Mario F. Buchely, Paul Kelly

Materials Science and Engineering Faculty Research & Creative Works

In this study, the influence of the rolling process on magnetic properties of Fe-3.3 wt% Si non-oriented electrical steel was investigated. The strip samples were cast using a high solidification cooling rate vacuum sampling method to simulate the solidification conditions of the industrial twin roll thin strip casting (TRSC) process. As-cast samples were subjected to various thermo-mechanical processing routes with different levels of hot-rolling (HR) and cold-rolling (CR). The influence of carbon and sulfur (C&S) contents in the steel were also investigated. Core loss (P1.5/50, P1.5/60, P1.0/50, P1.0/60) and magnetic induction (B25, B50) of the final annealed strip samples were …

Mechanical Activation And Cation Site Disorder In Mgal2o4, Cole A. Corlett, Matthias D. Frontzek, Nina Obradovic, Jeremy Lee Watts, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

The synthesis and crystallographic site occupancy were investigated for MgAl2O4 with and without mechanical activation of the precursor powders. Heating to 1200 °C or higher resulted in the formation of a single spinel phase regardless of whether the powders were mechanically activated or not. Neutron diffraction analysis was used to determine cation site occupancy and revealed that mechanical activation resulted in a lower degree of cation site inversion compared to the nonactivated materials, which indicated that the powders were closer to thermodynamic equilibrium. This is the first study to characterize the effects of mechanical activation on crystallographic site occupancy in …

Ultrafast Stiffening Of Concentrated Thermoresponsive Mineral Suspensions, Sharu Bhagavathi Kandy, Iman Mehdipour, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Edward Garboczi, Samanvaya Srivastava, Torben Gaedt, Gaurav Sant

Materials Science and Engineering Faculty Research & Creative Works

Extrusion-based 3D printing with rapidly hardening polymeric materials is capable of building almost any conceivable structure. However, concrete, one of the most widely used materials for large-scale structural components, is generally based on inorganic binder materials like Portland cement. Unlike polymeric materials, a lack of precise control of the extent and rate of solidification of cement-based suspensions is a major issue that affects the ability to 3D-print geometrically complex structures. Here, we demonstrate a novel method for controllable-rapid solidification of concentrated mineral suspensions that contain a polymer binder system based on epoxy and thiol precursors as well as one or …

Processing And Mechanical Properties Of Hot-Pressed Zirconium Diboride – Zirconium Carbide Ceramics, Eric W. Neuman, William Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

ZrB2 was mixed with 0.5 wt% carbon and up to 10 vol% ZrC and densified by hot-pressing at 2000 °C. All compositions were > 99.8% dense following hot-pressing. The dense ceramics contained 1–1.5 vol% less ZrC than the nominal ZrC addition and had between 0.5 and 1 vol% residual carbon. Grain sizes for the ZrB2 phase decreased from 10.1 µm for 2.5 vol% ZrC to 4.2 µm for 10 vol% ZrC, while the ZrC cluster size increased from 1.3 µm to 2.2 µm over the same composition range. Elastic modulus was ~505 GPa and toughness was ~2.6 MPa·m½ for all compositions. …

Machine Learning Mosa Monitoring System, Aditya G. Manjunath, Sabahudin Vrtagic, Fatih Dogan, Milan Dordevic, Mileta Zarkovic, Jasmin Kevric, Goran Dobric

Materials Science and Engineering Faculty Research & Creative Works

This research paper deals with the problem of Metal-Oxide Surge Arrester (MOSA) condition monitoring and a new methodology in surge arrester monitoring and diagnostics is presented. A machine learning algorithm (back propagation regression) is used to estimate the non-linearity coefficient of the surge arrester, based on operating voltage and leakage current of the arrester. Using a simulated system, this research investigates the possibility of application and efficiency of machine learning. It is shown that the applied learning algorithm results are competitive with the model results parameters calculated as R2 = 0.999 and mean absolute real error computed as 0.005 which …

Understanding Charge Effects On Marked Ball Wear Rates – A Corrosion Study, John Bailey Fletcher

Masters Theses

"To measure the wear rates of grinding balls within a ball mill, marked ball wear tests (MBWTs) have been used extensively. Using the wear rates from a MBWT, operators select the most cost-effective media for their grinding application. One factor that a MBWT does not account for is the possible interaction between different media materials which could affect their corrosion rates. Galvanic coupling between dissimilar metals can cause significant changes in their corrosion rates. While galvanic interactions between minerals and grinding media have been studied, the interaction between dissimilar media has not. Corrosion rates and potentials of modern high carbon …

Elevated Temperature Thermal Properties Of Zrb2-B4c Ceramics, Eric W. Neuman, Matthew Thompson, William Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

The elevated temperature thermal properties of zirconium diboride ceramics containing boron carbide additions of up to 15 vol% were investigated using a combined experimental and modeling approach. The addition of B4C led to a decrease in the ZrB2 grain size from 22 µm for nominally pure ZrB2 to 5.4 µm for ZrB2 containing 15 vol% B4C. The measured room temperature thermal conductivity decreased from 93 W/m·K for nominally pure ZrB2 to 80 W/m·K for ZrB2 containing 15 vol% B4C. The thermal conductivity also decreased as temperature increased. For nominally pure ZrB2, the thermal conductivity was 67 W/m·K at 2000 °C …

Superhard Single-Phase (Ti,Cr)B2 Ceramics, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Laura Silvestroni

Materials Science and Engineering Faculty Research & Creative Works

A nominally pure and dense (Ti0.9Cr0.1)B2 ceramic was produced by spark plasma sintering of powders synthesized by boro/carbothermal reduction of oxides. The synthesized powders were a single phase and had an average particle of 0.4 ± 0.1 μm and an oxygen content of 1.2 wt%. Average Vickers hardness values of the resulting ceramics increased from 25.9 ± 0.8 GPa at a load of 9.81 N, to 46.3 ± 0.8 GPa at a load of 0.49 N. Compared to the nominally pure TiB2 ceramic obtained under the same processing conditions, the (Ti0.9Cr0.1)B2 ceramic had higher values under the same load due …

Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Poor workability is a common feature of calcium sulfoaluminate (CSA) cement paste. Multiple chemical admixtures, such as set retarders and dispersants, are frequently employed to improve the workability and delay the setting of CSA cement paste. A quantitative assessment of the compatibility, efficiency, and the effects of the admixtures on cement paste workability is critical for the design of an appropriate paste formulation and admixture proportioning. Very limited studies are available on the quantitative rheology-based method for evaluating the workability of calcium sulfoaluminate cement pastes. This study presents a novel and robust time-dependent rheological method for quantifying the workability of …