Materials Science and Engineering Commons^™

Development Of Iii-V And Iv Epitaxy On Sapphire Technology, Emmanuel Wangila

Graduate Theses and Dissertations

This research presents comprehensive insights into the epitaxial growth of germanium (Ge) on c-plane sapphire substrates using molecular beam epitaxy (MBE). The direct growth of Ge on sapphire typically yields three-dimensional (3D) Ge islands with diverse growth directions, multiple primary domains, and twinned crystals. However, incorporating a thin AlAs nucleation layer proves instrumental in enhancing surface and material quality. With a 10 nm AlAs layer, the achieved surface exhibits improved characteristics, including a smoother surface, single epitaxial orientation, sharper rocking curve, and a single domain. This study surpasses previous works by achieving a single primary domain and reducing twinning. Furthermore, …

Computational Alchemy: Pioneering Spintronic, Thermoelectric, And Optoelectronic Materials Design Through First-Principles Calculations And Machine Learning, Eesha Sanjay Andharia

Graduate Theses and Dissertations

Intelligent materials discovery and design plays a pivotal role in advancement of spintronics, optoelectronics and thermoelectric devices and technology. In this study, we investigate three types of materials using first principles calculations. First, the structural, electronic, and magnetic properties of CrTiCoZ (Z = Al, Si) equiatomic quaternary Heusler alloys were investigated. CrTiCoAl compound was found to exhibit a half metallic ferromagnetic structure and Curie temperature above room temperature, which makes it an ideal candidate for magnetic tunnel junction, the basic building block of Spintronic devices. Second, we use Green’s function to obtain the finite temperature phonons by including quartic anharmonicity …

Modeling Powder Spreadability In Powder-Based Processes Using The Discrete Element Method, Austin T. Sutton, M. Hossein Sehhat, Ming C. Leu, Joseph W. Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Powder-bed fusion (PBF) processes refer to a subset of Additive Manufacturing (AM) techniques where powder is spread on the build-plate before melting (by a laser or electron beam). While PBF processes are attractive due to their ability for realizing complex structures that are either difficult or impossible to create through conventional means, the parts fabricated with these techniques can exhibit defects such as pores, inclusions, and excessive surface roughness. To minimize these defects, much research has been dedicated towards process maturation by optimizing laser or electron beam parameters. However, these developmental efforts typically do not address the recoating process where …

Pulsing-Induced Healing Of A Surface Crack Of A Nickel-Based Alloy, Liwei Wang, Mingming Quan, Zhen Tan, Ming Liu, Dianlong Wang, Xiao Yang, Ying Liu, Yaning Mao, Zhimin Liang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we demonstrate the feasibility of applying electric pulses to heal surface cracks on nickel-based alloy GH4169 under compressive load. There exists an incubation time for the onset of the healing of a crack, which is associated with local temperature at the crack tip. The crack size decreases with increasing the pulsing time at a constant healing rate prior to complete healing of the crack. Increasing compressive load accelerates the healing process. The electric pulsing leads to the formation of an influential zone surrounding the crack with the finest grain sizes in the healed crack and the coarsest …

Extreme Value Statistics Analysis Of Process Defects In Additive Manufacturing Materials, Ayorinde E. Olatunde, Kristen Hernandez, Austin Ngo, Arafath Nihar, Thomas G. Ciardi, Rachel Yamamoto, Pawan K. Tripathi, Roger H. French, John J. Lewandowski, Anirban Mondal

Faculty Scholarship

Fatigue and fracture studies focused on process defects that occur in Additive Manufacturing (AM) materials have shown that defect populations possess features which are better measured with extreme value statistics (EVS). In AM alloys, defect occurrences increase with material volume. This situation facilitates the need to model process defects in the path of fatigue crack growth with suitable statistical tools, such as EVS, which is more cost-effective when compared to destructive experiments. The application of EVS on defect space features helps determine the difference in defects present on fracture surfaces. As the fatigue quality of any material depends on its …

Photodegradation Of Microplastics Through Nanomaterials: Insights Into Photocatalysts Modification And Detailed Mechanisms, Yiting Xiao, Yang Tian, Wenbo Xu, Jun Zhu

Biological and Agricultural Engineering Faculty Publications and Presentations

Microplastics (MPs) pose a profound environmental challenge, impacting ecosystems and human health through mechanisms such as bioaccumulation and ecosystem contamination. While traditional water treatment methods can partially remove microplastics, their limitations highlight the need for innovative green approaches like photodegradation to ensure more effective and sustainable removal. This review explores the potential of nanomaterial-enhanced photocatalysts in addressing this issue. Utilizing their unique properties like large surface area and tunable bandgap, nanomaterials significantly improve degradation efficiency. Different strategies for photocatalyst modification to improve photocatalytic performance are thoroughly summarized, with a particular emphasis on element doping and heterojunction construction. Furthermore, this review …

Metallurgical Impact Of Switching From Hammer Units To Hydraulic Presses For Forging, Cole Hawker, Jacob Reed

Materials Engineering

Carlton Forge Works (CFW) is evaluating the retirement of its hammer units in favor of hydraulic presses to address safety concerns in forging aerospace components. This paper investigates the metallurgical implications of this transition, emphasizing the importance of superior microstructures and meeting industry standards and customer requirements. The alloys in question are Titanium-6Al-4V (Ti64) and Inconel 718 (INCO 718), which comprise a majority of CFW’s production. Ti64's high specific strength and thermal stability make it ideal for aerospace applications, while INCO 718 is recognized for superior high-temperature creep performance. Defects like freckles and white spots in INCO 718 are analyzed …

Development Of 485 Mpa Class High Strength Low Alloy Steel For Power Plant Infrastructures, Agung Baskoro, Rini Riastuti

Journal of Materials Exploration and Findings

Currently, Indonesia is progressing to build 35,000 MW of power plants, which will increase the demand for materials, especially steel. One of these power plants is fossil fuel-based, which generates not only electricity but also flue gas containing sulfur that may cause corrosion to power plant infrastructure such as chimney or boiler areas. In addition, apart from being resistant to corrosion in sulfuric and hydrochloric acid conditions, the steel used in power plant infrastructure must also have good strength, toughness, and weldability. Therefore, the present paper describes about steel development for power plant applications that has not only corrosion resistance …

Engineering Composite Gridlines For Improved Solar Module Reliability, Andre Chavez

Electrical and Computer Engineering ETDs

Renewable energy sources, such as solar power, are rapidly expanding worldwide to meet increased energy demands. However, these sources are exposed to challenging environmental stressors, such as extreme wind, heavy snow loads, and hailstorms that can cause irreversible damage to the crystalline semiconductor solar cells. Today, single crystalline silicon solar cells dominate the market, and our work is focused on improving their reliability against environmental stressors. One of the main degradation mechanisms caused by environmental stressors is cell cracks. These microcracks can go virtually undetected and lead to reduced power output from solar modules over time. To solve this engineering …

Characterization Of Chopped Carbon Fiber Reinforced Composites Produced Using Fused Deposition Modeling, Jonathon Tran, Rachel Shubella

Student Research Symposium

Fused deposition modeling (FDM) is an additive manufacturing (AM) process which can create parts with complex geometries in their final shape without need for additional specialized tools or devices. The FDM process builds parts by adding material layer by layer only where it is needed, saving energy, costs, production time for complex parts, and minimizing waste. Fiber reinforcement can significantly enhance the mechanical properties of a polymer material and depends significantly on the fiber length distribution and fiber orientation distribution of the final part. In this research, we investigated the various infill patterns of FDM printed Markforged onyx which is …

Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt, Jackson Ivory

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The electrochemical behavior of uranium FLiNaK molten salts is explored, focusing on cyclic voltammetry (CV) as a powerful tool for redox characterization and diffusion studies. Through a comprehensive review of recent research, the study highlights the significance of CV in understanding electrode kinetics, material compatibility, and process optimization in molten salt environments. The findings underscore the potential of FLiNaK molten salt reactors in advancing nuclear energy technologies, fuel processing, and waste management strategies. Collaborative interdisciplinary efforts are emphasized to address challenges and accelerate innovation in electrochemical methods for nuclear applications.

An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction, Cameron Vann

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The process of generating chlorine gas using electrolysis in aqueous systems is well established. However, a new process requires chlorine to be generated at high temperatures using molten salt. This harsh environment requires a new study of anode materials for the chlorine evolution reaction. Anode materials can be compared by their kinetic parameters, the transfer coefficient α and the exchange current i0. The basic theory of these properties as they relate to the chlorine evolution reaction has been detailed and an analysis method for finding these effective parameters has been shown and demonstrated.

Electrical Resistance Tomography Measurements In Column Flotation Of Pure Hydrophobic And Hydrophilic Systems, Vimeipha Vilayphone

Graduate Theses & Non-Theses

Column flotation was phenomenologically investigated with Electrical Resistance Tomography (ERT) as an uninterrupted instrument to measure gas holdup. Two-phase tests were performed to use the measurements for examining gas dispersion. Results were found to duplicate the findings in a previous thesis. With confidence attained in experimental procedures, three-phase tests were then performed to compare gas holdup with hydrophobic and hydrophilic solids. Hydrophobic solids included talc as well as dolomite with dodecyl amine (DDA) collector. Hydrophilic solids included dolomite as well as talc with carboxymethyl cellulose (CMC) depressant. Variables throughout the research included frother concentration and sparger size. Results showed gas …

Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing, Oluwatosin Adebayo, Richard Ladouceur, Zainab Nasrullah

Graduate Theses & Non-Theses

The adsorption capacity for six rare earth elements (Lanthanum, Terbium, Neodymium, Dysprosium, Praseodymium, and Holmium) by biochar produced from hemp feedstock was investigated. An innovative approach to enhancing the adsorption of rare earth elements using biochar was studied and investigates the potential of resonant vibratory mixing (RVM) as a process intensification method compared to conventional mechanical mixing for the adsorption process. Hemp hurds as source of biomass was pyrolyzed to produce biochar at a temperature of 4500C for 60 minutes. The biochar was characterized by FTIR (Fourier Transform Infra-red), SEM (Scanning Electron Microscopy), Surpass 3 Electrokinetic solid surface analyzer, and …

Tin-Silver As A Novel Biodegradable Metallic Biomaterial, Charley Goodwin

All Dissertations

The Essure device is a non-hormonal, minimally-invasive, permanent female sterilization implant, removed from the market due to an increase in adverse events, hypothesized to be caused by corrosion of the Sn-Ag component of the implant. The goals of this dissertation were to first develop implant retrieval methods for Essure devices and surrounding tissue, documenting signs of degradation and metallic degradation products, then to characterize the electrochemical behavior of Sn-Ag in biologically representative environments and finally, to assess the biological interaction of Sn-Ag. Retrieval analyses developed successful methods, qualifying the degree of corrosion, primarily of the Sn-Ag component and finding Sn …

Synthesis Of Bimetallic Nickel And Cobalt Phosphide Nanostructures For Electrocatalysis, Sarah Meixin York

Graduate Theses and Dissertations

Transition metal phosphides have become a new class of materials to be considered as promising catalysts for a number of applications including electrochemical hydrogen evolution (HER). Electrocatalysis in hydrogen evolution is a heavily studied field due to the increasing desire to develop more efficient and more cost-effective catalysts for clean hydrogen production. This project develops a chemical approach to synthesizing bimetallic cobalt-nickel phosphide nanostructures for their use in HER. The synthesis is accomplished by thermal decomposition of the metal precursors in the presence of carbon monoxide (CO) and trioctyl phosphine (TOP). The resulting nanostructures were characterized using transition electron microscopy …

Mechanical Characterization And Evaluation Of Additively Manufactured Titanium 5v-5mo-5al-3cr Alloy, Zachary Casias

Mechanical Engineering ETDs

Ti-5V-5Mo-5Al-3Cr (Ti-5553) is a near beta titanium alloy commonly used in aerospace applications. It is currently being explored for additive manufacturing (AM), but the fatigue behavior of this AM alloy needs to be well-understood for adoption in aerospace applications. The present work examines the tensile and fatigue behavior of LPBF manufactured Ti-5553. The effect of post-print heat treatments, effects of surface roughness, and print defects on the mechanical properties of AM Ti-5553 were also evaluated. Fatigue lives of as-LPBF and BAA material are nearly identical, and both are far below the fatigue lives of conventionally manufactured Ti-5553 of 350 MPa. …

Thermo-Gravimetric Analysis Of Variables Of Oxidization, Clark Nguyen, Mario F. Buchely

Undergraduate Research Conference at Missouri S&T

Oxidation phenomena play a critical role in high temperature metallurgical processing and the performance during life cycle of components made of both high and low alloy steels. Therefore, the development of a precise experimental methodology to quantify oxidation processes is critically important. This report summarizes my experimental study of the oxidation behavior of high and low alloy steel, including kinetics of surface oxide layer formation and spallation. The focus of study was in determining the complex interactions between alloying elements in steel matrix and oxidation environment, composition and surface morphology of formed oxides. This report will also explore how the …

Thermogravimetric Analysis Of High & Low Alloy Steel, Clark Nguyen

Undergraduate Research Conference at Missouri S&T

Oxidation phenomena play a critical role in high temperature metallurgical processing and the performance during life cycle of components made of both high and low alloy steels. Therefore, the development of a precise experimental methodology to quantify oxidation processes is critically important. This report summarizes my experimental study of the oxidation behavior of high and low alloy steel, including kinetics of surface oxide layer formation and spallation. The focus of study was in determining the complex interactions between alloying elements in steel matrix and oxidation environment, composition and surface morphology of formed oxides. This report will also explore how the …

A Guide To Fifty Years Of Research At Montana Tech: Part 3-Decontamination Of Ratioactively Contaminated Steel By Melt Refining/Slagging Processing, Larry G. Twidwell, Samuel A. Worcester

Metallurgy

This presentation includes a discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering. The discussion is focused on Decontamination of Radioactively Contaminated Steel by Melt Refining/Slagging. This presentation is based on the research of Master of Science graduate students, industrial and academic colleagues, at the Montana College of Mineral Science and Technology (which morphed to Montana Tech [1977], then to Montana Tech of The University of Montana [2000], then to Montana Technological University [2019]). The referenced work of each of the graduate students in this presentation is gratefully acknowledged. The following summary presentation …

Segregation And Heat Treatment Response Of Cast Quench And Partition Steels, Mujeeb Hussain Shaik

Masters Theses

Quench and partition (Q&P) steels have emerged as promising alternatives to traditional quenching and tempering methods, offering a superior balance of strength and ductility due to their unique microstructure of martensite, and retained austenite. This literature review examines the development and optimization of Q&P steels, focusing on their mechanical properties, heat treatment processes, and applications in various industries. This study explores the application and effectiveness of the Quench and Partition (Q&P) heat treatment process on cast steels and examines segregation phenomena in cast medium Mn steels. Medium Mn steels were employed for various Q&P cycles on cast specimens to investigate …

The Behavior Of ½⟨111⟩ Screw Dislocations In W–Mo Alloys Analyzed Through Atomistic Simulations, Lucas A. Heaton, Kevin Chu, Adib J. Samin

Faculty Publications

Analyzing plastic flow in refractory alloys is relevant to many different commercial and technological applications. In this study, screw dislocation statics and dynamics were studied for various compositions of the body-centered cubic binary alloy tungsten–molybdenum (W–Mo). The core structure did not appear to change for different alloy compositions, consistent with the literature. The pure tungsten and pure molybdenum samples had the lowest plastic flow, while the highest dislocation velocities were observed for equiatomic, W_0.5Mo_0.5 alloys. In general, dislocation velocities were found to largely align with a well-established dislocation mobility phenomenological model supporting two discrete dislocation mobility regimes, …

Inhibited Surface Diffusion In Nanoporous Multi-Principal Element Alloy Thin Films Prepared By Vacuum Thermal Dealloying, Tibra Das Gupta, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Nanoporous structures with 3D interconnected networks are traditionally made by dealloy- ing a binary precursor. Certain approaches for fabricating these materials have been applied to refrac- tory multi-principal element alloys (RMPEAs), which can be suitable candidates for high-temperature applications. In this study, nanoporous refractory multi-principal element alloys (np-RMPEAs) were fabricated from magnesium-based thin films (VMoNbTaMg) that had been prepared by magnetron sputtering. Vacuum thermal dealloying (VTD), which involves sublimation of a higher vapor pres- sure element, is a novel technique for synthesizing nanoporous refractory elements that are prone to oxidation. When VMoNbTaMg was heated under vacuum, a nanoporous structure was …

Synthesis Of Ni-Based Intermetallics By Electrolytic Plasma Processing Of Ti And Ti-Based Alloys, Chuzhong Zhang

Material Science and Engineering Dissertations - Archive

EPP is an innovative surface modification technique that enables the deposition of metal ions from the electrolyte and their integration with substrate atoms to form intermetallic compound surface layers. EPP offers advantages such as high deposition rates, environmental cleanliness, and operational simplicity. In this study, Ni-Ti intermetallic layers were successfully synthesized on a Ti-6Al-4V substrate using EPP. The properties of the resulting Ni-Ti intermetallic layers were characterized using SEM, EDS, XRD, TEM, nanoindentation, and tribology tests.

This work aims to understand the fabrication mechanism and investigate the effects of various processing parameters on the EPP process. Key factors such as …

Quantitative Modeling Of Micro Discharge And Oxide Growth In Plasma Electrolytic Oxidation Of Titanium, Kingsley I. Ochiabuto

Material Science and Engineering Dissertations - Archive

Plasma electrolytic oxidation (PEO) has been extensively applied in the past to improve the tribological properties of titanium and its alloys allowing their widespread use in industrial applications. However, the complete PEO mechanism of action remains unclear. While there are several mathematical models providing useful insights into the PEO process, they do not fully incorporate the effect of applied potential on the outcomes of PEO. In this work, we develop an experimentally informed computational model by expanding on the dielectric breakdown model. We incorporate experimental data to extract key parameters, exploring the iterative dependency of the oxide thickness and ionic …

Solidification Cracking In Additively Manufactured High Entropy Alloy Nicrcofe With V Or W, Andrew R. Walch

Dissertations, Master's Theses and Master's Reports

Recent sustainability efforts have reduced CO2 emissions from electricity generation by increasing operating temperatures and pressures in advanced ultra-supercritical (A-USC) power plants. However, the extreme operating conditions in these A-USC power plants require new high temperature materials. The recent study of nickel-based high-entropy alloys (HEA) represents the latest approach to meet the specifications for A-USC operations. A CALculation PHase Diagram (CALPHAD) driven Bayesian optimization method was used to design the composition of alloys composed of NiCrCoFe with V or W, which were fabricated via wire-based additive manufacturing to enable high throughput development. Although the alloy was designed to minimize solidification …

Using Tensile And Compressive Stress Superposition During Incremental Forming To Manipulate Martensitic Transformation In Ss304, Elizabeth M. Mamros, Fabian Maaß, A. Erman Tekkaya, Brad L. Kinsey, Jinjin Ha

Faculty Conference Papers and Presentations

Single point incremental forming (SPIF) is a flexible manufacturing process that has applications in industries ranging from biomedical to automotive. In addition to rapid prototyping, which requires easy adaptations in geometry or material for design changes, control of the final part properties is desired. One strategy that can be implemented is stress superposition, which is the application of additional stresses during an existing manufacturing process. Tensile and compressive stresses applied during SPIF showed significant effects on the resulting microstructure in stainless steel 304 truncated square pyramids. Specifically, the amount of martensitic transformation was increased through stress superposed incremental forming. Finite …

Parametric Optimization Of Friction Stir Welding Of Aa6061-T6 Samples Using The Copper Donor Stir-Assisted Material Method, Aiman H. Al-Allaq, Joseph Maniscalco, Srinivasa Naik Bhukya, Zhenhua Wu, Abdelmageed Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

This study presents an optimization of the process parameters for the effect of copper (Cu) donor material percentage on the friction stir welding (FSW) of AA6061-T6 alloy. Extensive factorial experiments were conducted to determine the significance of the rotational speed (ω), the transverse speed (v), the interface coefficient of friction (μ), and the Cu donor material percentage in the plunge, left, right, and downstream zones. Design Expert 13 software was used to identify the number of simulation experiments to be conducted using the Abaqus simulation software. From Design Expert 13, which is a thorough multi-objective optimization analysis software, we were …

Mechanisms Of Dendritic Shorting In Lithium Metal Batteries With Li7la3zr2o12 Solid Electrolytes, Lukas Karapin-Springorum

Pomona Senior Theses

Energy storage will play a crucial role in efforts to mitigate the effects of climate change caused by greenhouse gas emissions from human activity. Lithium metal batteries using solid electrolytes like Li₇La₃Zr₂O₁₂ have higher energy density than lithium-ion batteries, which may enable a more rapid and complete electrification of transportation. However, lithium metal batteries suffer from undesirable short-circuiting when metallic lithium deposits connect the two electrodes. It has been debated whether these lithium dendrites generally grow directionally from the anode or are generated by the reduction of lithium ions inside the solid electrolyte, …

B(C₆F₅)₃ Co-Catalyst Promotes Unconventional Halide Abstraction From Grubbs I To Enhance Reactivity And Limit Decomposition, Austin W. Medley, Diya Patel, Calvin Utne, Trandon A. Bender

Chemistry & Biochemistry Faculty Publications

Ruthenium based Grubbs metathesis has become a commonplace reaction for synthetic chemists. Development of new generations of catalysts evolving from Grubbs I (GI) have led to greater stability, functional group compatibility, and superior reactivities. However, these advancements lead to increased costs. To this end, we report here how the addition of the commercially available tris(pentafluorophenyl)borane Lewis acid, which has become a common place catalyst in its own right, leads to enhanced reactivity of GI. Moreover, the increased reactivity arises via halide abstraction rather than traditional phosphine dissociation, providing ring-opening metathesis polymerization products that are divergent from those synthesized without the …