Materials Science and Engineering Commons^™

Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field

Materials Science and Engineering Faculty Research & Creative Works

Nitrogen pickup during air induction melting can result in porosity and a loss of fracture toughness in ultrahigh-strength quenched and tempered steel castings. Nitrogen atoms are easily adsorbed into liquid steel upon exposure to the air, and argon shrouding alone has limited effectiveness. Previous studies have shown that proper charge sequencing and maintaining a high amount of dissolved oxygen in the melt prior to tapping and deoxidation can limit nitrogen pickup in the melt. In the current study, the effect of melt practice and charging procedure on nitrogen pickup was studied as a function of hold time in a series …

Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali

Materials Science and Engineering Faculty Research & Creative Works

Efficient oxide scale removal is critical for maintaining surface quality and process efficiency in steel manufacturing. This study optimizes water jet descaling by evaluating the performance of flat and rotary jet nozzles under varying process parameters. Using a combined approach of experimental analysis and computational fluid dynamics, it investigates the influence of pressure (138–275 bar), lead angle (0°, 15°, 25°), working distance (50–100 mm), and spray angle (15°–25°) on descaling efficiency. Findings indicate that flat jet nozzles achieve superior performance at short working distances due to concentrated impact forces, while rotary jet nozzles sustain efficiency over extended distances through dynamic …

Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck

Materials Science and Engineering Faculty Research & Creative Works

The effect of gating system design on the inclusion population and size distribution in an aluminum-killed low-alloy advanced high strength steel casting was studied. A mold with four different gating systems: pressurized and non-pressurized with side risers, naturally pressurized with a side riser, and naturally pressurized with a top riser, was designed using computational fluid dynamics and solidification software. The design allowed inclusion populations in castings produced with each gating system to be compared during the same pouring event. Samples taken from different positions just below the top surface of each casting were analyzed using an SEM/EDS system with automated …

High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Fe-based cast alloys, including cast irons and steels, have been used in service at a wide range of mechanical and thermal load in oxidizing environment. Special alloying practices can be used to improve high temperature performance of Fe-based cast alloys in an oxidizing atmosphere. At elevated temperatures, alloying elements can produce a protective interface layer which prevents oxidant penetration into the metal matrix. However, a combination of thermo-mechanical loads along with surface oxidation can decrease the materials integrity by destroying the stable protected interface limiting the range of working parameters and lifetime performance of the material. This overview aims to …

Roadmap To 100 Gwdc: Scientific And Supply Chain Challenges For Cdte Photovoltaics, B. Edward Sartor, Samantha B. Reese, Lorelle M. Mansfield, Ryan Muzzio, Chun Sheng Jiang, Eric Colegrove, John S. Mangum, Camden L. Kasik, Daniel Z. Shaw, James R. Sites, Ramesh G. Dhere, Alex B. Goldstone, Michael S. Moats

Materials Science and Engineering Faculty Research & Creative Works

This roadmap highlights pathways to expand the CdTe module manufacturing capacity per year to 100 GWDC by 2030 by improving Te extraction from existing supply chains, minimizing Te usage in modules by leveraging thinner absorbers, and focusing research efforts in key areas to improve module efficiencies. Both scientific and supply chain innovations will be necessary to maintain the high compound annual growth rate of the CdTe photovoltaic (PV) industry and cement its role as a key technology for multi-TW-scale PV deployment.

Pulsed Arc Additive Manufacturing Of A Functionally Graded Er2209 Duplex Stainless Steel And Hsla-100 Structure: Morphology, Characterization, And Mechanical Performance, Stevens G. Hill Jr

College of Graduate Studies: Theses & Dissertations

Wire arc additive manufacturing is a process well suited to the efficient production of large structures. Duplex stainless steel exhibits high corrosion resistance and good strength which can be highly beneficial for industrial use. However, its use is limited due to its cost and complexity in controlling microstructure to achieve desired properties. In many cases, it can be highly beneficial to manufacture a component which uses specialty steel grades such as duplex stainless steel only where necessary, and utilizes more affordable, commonly available steels for reinforcement or bulk structural support. A functionally graded material satisfies these requirements by providing a …

Effect Of Bioactive Glass On Pxdda / Pxdda-Co-Pla Nanocomposite For Hard Tissue Reconstruction: Synthesis And Characterization, Ehsan Vafa, Lobat Tayebi, Fatemeh Azizli, Somayeh Parham, Katayoon Rezaeeparto, Sedigheh Azadi, Ali Mohammad Amani, Mohammad Javad Azizli, Hesam Kamyab, Shreeshivadasan Chelliapan, Saravanan Rajendran

Electrical & Computer Engineering Faculty Publications

Newer bone graft materials face various challenges in achieving optimal mechanical strength, bioactivity, and antibacterial action simultaneously, which can result in suboptimal regeneration outcomes and increased infection risks In the present study, we developed a novel nanocomposite of poly (xylitol-co-dodecanedioic acid) (PXDDA) and poly (lactic acid) (PLA) with 1-10 wt% incorporation of bioactive glass (BG), utilizing a a PXDDAco-PLA compatibilizer for maintaining homogeneity. Extensive characterization techniques including, Fourier infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauere Emmette Teller (BET), Proton Nuclear Magnetic Resonance (¹H NMR) and contact angle measurements, revealed that the addition …

The Impact Of Chromium Ion Implantation On Ald Lead Chalcogenide Thin Films, Haifeng Cong, Charlotte Poterie, Jean Francois Barbot, Helmut Baumgart

Electrical & Computer Engineering Faculty Publications

Inherently the synthesis of semiconducting materials by Atomic Layer Deposition ALD produces only intrinsic undoped films which require the introduction of small amounts of impurities for doping to change them into extrinsic semiconductors. Apart from various in-situ diffusion doping techniques like delta doping during the ALD process, post deposition doping by ion implantation affords the best control of dose and doping profile. The present study investigates the impact of 180 keV Cr⁺ ion implantation on the properties of semiconducting ALD lead chalcogenide thin films to improve their thermoelectric figure of merit. The implantation was accomplished with 180 keV Chromium …

Quantifying Trapped Magnetic Vortex Losses In Niobium Resonators At Mk Temperatures, D. Bafia, B. Abdisatarov, R. Pilipenko, Y. Lu, G. Eremeev, A. Romanenko, A. Grassellino

Electrical & Computer Engineering Faculty Publications

Trapped magnetic vortices in niobium introduce microwave losses that degrade the performance of superconducting resonators. While such losses have been extensively studied above 1 K, we report here their direct quantification in the millikelvin and low-photon regime relevant to quantum devices. Using a high-quality factor 3D niobium cavity cooled through its superconducting transition in controlled magnetic fields, we isolate vortex-induced losses and find the resistive component of the sensitivity to trapped flux S to be approximately 2 n Ω/mG at 10 mK and 6 GHz. The decay rate is initially dominated by two-level system (TLS) losses from the native niobium …

Mxene-Based Materials For Enhanced Water Quality: Advances In Remediation Strategies, Ali Mohammad Amani, Milad Abbasi, Atena Najdian, Farzaneh Mohamadpour, Seyed Reza Kasaee, Hesam Kamyab, Shreeshivadasan Chelliapan, Mostafa Shafiee, Lobat Tayebi, Ahmad Vaez, Atefeh Najafian, Ehsan Vafa, Sareh Mosleh-Shirazi

Electrical & Computer Engineering Faculty Publications

Two-dimensional MXenes are promising candidates for water treatment because of their large surface area (e.g., exceeding 1000 m²/g for certain structures), high electrical conductivity (e.g., >1000 S/m), hydrophilicity, and chemical stability. Their strong sorption selectivity and effective reduction capacity, exemplified by heavy metal adsorption efficiencies exceeding 95 % in several studies, coupled with facile surface modification, make them suitable for removing diverse contaminants. Applications include the removal of heavy metals (e.g., achieving >90 % removal of Pb(II)), dye removal (e.g., demonstrating >80 % removal of methylene blue), and radioactive waste elimination. Furthermore, 3D MXene architecture exhibit enhanced performance in antibacterial …

Characterization And Deportment Of Anode Impurities In Copper Electrorefining, Charles Michael Campbell

Doctoral Dissertations

The objective of this research was to study the deportment of the group 15 elements, arsenic, antimony and bismuth during copper electrorefining. Samples were collected from six industrial copper anodes with different compositions. Specimens were physically characterized and electro refined to understand the differences in the behavior of selected impurities. Inclusions in the cast metal structures were characterized using automated scanning electron microscopy and energy dispersive spectroscopy to measure and correlate their size, shape and composition. Arsenic and lead were found to have a positive correlation between concentration and size of inclusions. Using wavelength dispersive spectroscopy, multiphase inclusions were examined, …

Iron Ore Tailings Reprocessing By Electrostatic Separation Plus Two Stages Froth Flotation, Vincent Bailey Arohunmolase

Dissertations, Master's Theses and Master's Reports

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. This study investigates the practicality of reprocessing tailings to enhance iron oxide content, combining electrostatic separation with a two-stage froth flotation process using oleic acid (direct flotation) and amine (reverse flotation). The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource utilization. The process aims to upgrade the iron oxide content to around 93-99% Fe₂O₃, making the recovered material suitable for the production of direct-reduced iron.

Electrostatic separation was …

Bayesian Alloy Design With Additive Synthesis, Michael R. Sulwer

Dissertations, Master's Theses and Master's Reports

To reduce carbon emissions and increase power out, steam powerplants need to increase the operating temperatures and pressures of steam turbines to improve efficiency. This necessitates the development of high temperature alloys with superior strength and stability. This research aims to design a class of solid solution High Entropy Alloys (HEAs) to exceed the high temperature performance of commercial alloys like Haynes 230 while maintaining comparable costs for Advanced Ultra Supercritical (A-USC) steam cycles. This project integrates Bayesian optimization and Calculation of Phase Diagrams (CALPHAD) within an Integrated Computational Materials Engineering (ICME) framework to predict and optimize key material properties: …

Exploration And Synthesis Of Tin Intermetallic Single Crystals, Jared L. Shortt

Graduate Theses/Dissertations

This thesis presents the synthesis and characterization of two tin-based intermetallic compounds: Mn₄.₁₂Sn and Ni₆Sn₈Ge₀.₄₇. Single crystals were grown using a high-temperature self-flux method, allowing for the formation of phase-pure samples suitable for structural and physical property analysis. The crystalline phases were identified and refined using powder and single-crystal X-ray diffraction (XRD), while scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS) was employed to verify stoichiometry and homogeneity. Magnetization measurements performed using a superconducting quantum interference device (SQUID) magnetometer revealed distinct magnetic behavior in the manganese-rich compound, while the nickel-based compound was explored for potential magnetic features arising from …

Potential Of Lidar And Hyperspectral Sensing For Overcoming Challenges In Current Maritime Ballast Tank Corrosion Inspection, Sergio Pallas Enguita, Jiajun Jiang, Chung-Hao Chen, Samuel Kovacic, Richard Lebel

Electrical & Computer Engineering Faculty Publications

Corrosion in maritime ballast tanks is a major driver of maintenance costs and operational risks for maritime assets. Inspections are hampered by complex geometries, hazardous conditions, and the limitations of conventional methods, particularly visual assessment, which struggles with subjectivity, accessibility, and early detection, especially under coatings. This paper critically examines these challenges and explores the potential of Light Detection and Ranging (LiDAR) and Hyperspectral Imaging (HSI) to form the basis of improved inspection approaches. We discuss LiDAR’s utility for accurate 3D mapping and providing a spatial framework and HSI’s potential for objective material identification and surface characterization based on spectral …

Preparation Of Mocvd-Grown Photocathodes Containing A Strained Gaas/Gaasp Superlattice, G. Blume, A. Masters, J. Grames, M. Stutzman, M. Grau, S. Marsillac

Physics Faculty Publications

In this work, we investigate heat cleaning options for high-polarization GaAs/GaAsP strained-superlattice (SSL) photocathodes with a distributed Bragg reflector (DBR) that were grown using metalorganic chemical vapor deposition (MOCVD). This was done using a microMott polarimeter at Jefferson Lab to optimize both quantum efficiency and polarization. The fabrication process for MOCVD-grown photocathodes does not allow for the inclusion of an arsenic cap, contrary to what is done when fabricating photocathodes using molecular-beam epitaxy (MBE). Without proper preparation, the performance of MOCVD-grown photocathodes can be limited due to surface contamination. Here, we varied both duration and temperature of the heat cleaning …

Surface Chemistry And Adsorption Mechanism Of Orfom® D8 For Cu Depression In Cu-Mo Flotation, Patrick Jeff Mensah

Graduate Theses & Non-Theses

In traditional chalcopyrite-molybdenite (Cu-Mo) flotation separation systems, inorganic depressants such as NaSH and NaCN are used to selectively depress chalcopyrite making it more hydrophilic so molybdenite can be floated and recovered. NaSH and NaCN are highly toxic, have high explosion potential, strong odor, and readily oxidize in air resulting in a high consumption rates. To control oxidation, nitrogen gas, and Nokes reagent are both necessary, making the process even more expensive. In addressing these challenges, attention is fast shifting to disodium carboxymethyl trithiocarbonate (Orfom® D8), a novel organic depressant designed to replace conventional inorganic depressants because it does not easily …

Multiphysics Modeling And Experimental Validation Of High-Strength Steel In Laser Powder Bed Fusion Process, M. Rangapuram, S. Babalola, J. W. Newkirk, L. N. Bartlett, F. W. Liou, K. Chandrashekhara, Stephen R. Cluff

Materials Science and Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a subset of the additive manufacturing process in which a laser beam selectively joins the metal powder into a desired part in a sequential layer process. Owing to its complex nature of rapid heating and cooling of the melt pool, there is a need to understand the melt pool behavior and its effects on the final manufactured part. a densely packed powder bed is highly desirable for fabricating a superior part using the LPBF process. in this work, discrete element model was used to generate powder beds with realistic powder properties and various factors …

A General Model For The Ductility Of Intermetallics Applied To Fe-Co Alloys, Wesley Everhart, Joseph Newkirk

Materials Science and Engineering Faculty Research & Creative Works

The mechanical properties, specifically ductility, of high performing soft magnets such as Fe-Co alloys are a limiting factor to their broader use in a number of systems. The understanding of the mechanical robustness in these materials is currently insufficient to be able to support the growing interest in applications such as magnetic shielding or electric motors. Fe-Co alloys provide the highest commercially available magnetic saturation and high magnetic permeability but have very poor ductility. The addition of vanadium to these alloys has allowed for significant commercialization and some ductility improvements, but the fundamental reasons for the observed improvements are not …

Atmosphere Effects In Laser Powder Bed Fusion: A Review, Ben Brown, Cody Lough, Davis Wilson, Joseph Newkirk, Frank Liou

Materials Science and Engineering Faculty Research & Creative Works

The use of components fabricated by laser powder bed fusion (LPBF) requires the development of processing parameters that can produce high-quality material. Manipulating the most commonly identified critical build parameters (e.g., laser power, laser scan speed, and layer thickness) on LPBF equipment can generate acceptable parts for established materials and moderately intricate part geometries. The need to fabricate increasingly complex parts from unique materials drives the limited research into LPBF process control using underutilized parameters, such as atmosphere composition and pressure. As presented in this review, manipulating atmosphere composition and pressure in laser beam welding has been shown to expand …

Optimizing The Physical Properties Of Biochar For Co2 Adsorption Using Resonant Vibrations, Amirhosein Riahi, Richard Ladouceur

Mining Engineering

Among various Carbon Capture and Sequestration (CCS) technologies, significant emphasis has been placed on biochar as an effective post-combustion CO2 capture method. Biochar demonstrates potential as a technically effective method for stabilizing carbon. However, the efficacy of CCS based on adsorption phenomenon depends on factors such as the CO2 uptake of the adsorbent, kinetic rates, and cyclic adsorption. The study shows that Low-Frequency High Amplitude (LFHA) resonant vibratory mixing improves the physical characteristics and adsorption properties of hemp biochar. According to the results of an analysis of variance (ANOVA), increasing both the mass of biochar and the intensity of resonant …

Computational Modeling Of High Yttrium Refractory High Entropy Alloy Microstructures, Kaleb C. Ryan, Marissa M. Baker

College of Engineering Summer Undergraduate Research Program

Refractory high entropy alloys (RHEAs) are advanced metals made up of five or more principal elements in roughly equal amounts. The microstructural effects of alloying with yttrium as a principal element for RHEAs are currently not well understood. This project compared RHEA microstructures from literature with simulations using the High Entropy Alloy Predicting Software (HEAPS), which computes 10 screening criteria to predict the microstructure of a RHEA composition. The accuracy of HEAPS predictions was assessed by comparing them with experimentally validated microstructures found in literature. A combination of criteria was found to have a 95.8% accuracy rate, and a new …

Development Of Robust Steel Alloys For Laser-Directed Energy Deposition Via Analysis Of Mechanical Property Sensitivities †, Jonathan Kelley, Joseph W. Newkirk, Laura N. Bartlett, Sriram Praneeth Isanaka, Todd Sparks, Saeid Alipour, Frank Liou

Materials Science and Engineering Faculty Research & Creative Works

To ensure consistent performance of additively manufactured metal parts, it is advantageous to identify alloys that are robust to process variations. This paper investigates the effect of steel alloy composition on mechanical property robustness in laser-directed energy deposition (L-DED). In situ blending of ultra-high-strength low-alloy steel (UHSLA) and pure iron powders produced 10 compositions containing 10–100 wt.% UHSLA. Samples were deposited using a novel configuration that enabled rapid collection of hardness data. The Vickers hardness sensitivity of each alloy was evaluated with respect to laser power and interlayer delay time. Yield strength (YS) and ultimate tensile strength (UTS) sensitivities of …

Experimental Investigation And Evaluation Of Mechanical Properties And Microstructural Characterization On Chromium Molybdenum Steel Processed Through Laser Based Welding, Rakesh S

Theses and Dissertations

Creep Strength Enhanced Ferritic (CSEF) martensitic modified 9Cr-1Mo (P91) steel is extensively employed in fast breeder nuclear reactors and thermal power plants owing to its superior resistance to thermal fatigue and oxidation corrosion compared with other low-alloy steels. Despite its excellent high-temperature performance, the weldability of this steel remains a critical concern.

Conventional arc welding processes generate excessive heat input and complex thermal cycles, resulting in heterogeneous microstructures, retention of δ-ferrite, and subsequent degradation in service life. In contrast, high energy density beam welding techniques such as laser and electron beam welding offer precise thermal control and minimal heat-affected zones …

Utilization Of Sodium Flame Synthesis For The Formation And Deposition Of Pure Metal Materials For Applications In Additive Manufacturing, Zachariah Wargel

McKelvey School of Engineering Graduate Student Theses & Dissertations

Advanced material classes, such as high temperature alloys, ceramics, and refractory materials have become a key area of focus for expansion in the realm of additive manufacturing. Factors such as high melting points, material homogeneity, and physical properties such as ductility limit the application of popular additive manufacturing methods to these material classes. By utilizing sodium flame synthesis and deposition (SFD) technology, nanoparticle materials can be synthesized via combustion in a laminar co-flow diffusion burner and impacted such that the deposits can be used to manufacture designed components. By using the applicable precursor materials of metal chlorides and elemental sodium …

Effect Of Impurities In Supercritical Co2 Environment On Steel Corrosion Behavior – An Overview, Shilla Rizqi Widianto, Johny Wahyuadi Soedarsono, Rini Riastuti, Badrul Munir

Journal of Materials Exploration and Findings

Carbon capture, utilization, and storage (CCUS) technology is one of the available technologies to reduce presence of greenhouse gasses. Implementation of CCUS technology strongly relates with the CO₂ transportation from the capturing facility to the storage in the geological reservoir. The most economical method for large-scale and long-distance CO₂ transportation is using pipeline in supercritical phase. Moreover, presence of impurities such as water, O₂, SO₂, H₂S, NO₂ may cause detrimental effect towards carbon steel pipeline. This paper intends to provide an initial information for supercritical CO₂ pipeline material selection, which …

Hollow Connecting Rod Thin Wall Austempered Ductile Iron (Twadi) For Manufacturing Light Weight Components, Ricardina Freitas Da Silva, Bambang Suharno, Rianti Dewi Sulamet-Ariobimo

Journal of Materials Exploration and Findings

Efforts made by the automotive industry to reduce energy consumption have encouraged researchers to carry out various studies. One way is to make components lighter by casting thin wall austempered ductile iron (TWADI). Reducing the weight of components such as connecting rods (conrod) will result in lower energy consumption, but provided that these components still meet standards in terms of mechanical properties and microstructure or even exceed them. In this research, design optimization was applied to conrod by making the area I-beam zero mm (hollow), with hope that it can replace conrod Vespa PX-150. While the manufacturing process is divided …

Analysis Risk Based Inspection Api 581 On Lpg Spherical Tank At Pt. Xyz, Sigit Trahmawan, Eddy Sumarno Siradj, Jaka Fajar Fatriansyah

Journal of Materials Exploration and Findings

Liquified petroleum gas (LPG) spherical tanks are pressure vessel equipment for storing fuel gas products. The high pressure along with the fuel gas inside as flammable and combustible substance means that this equipment might result major accident hazard such as explosion, fires and environmental pollution. This study is aimed calculated and mitigate risk on 500 metric ton capacity LPG spherical tank using Risk-based inspection (RBI) analysis method that makes risk as its foundation. This RBI method uses quantitative analysis referring to API 581 to determine the risk of LPG Spherical Tank by determining the probability of failure (PoF) and the …

Settingsorder Article Reprints Open Accessarticle A Model To Account For The Effects Of Load Ratio And Hydrogen Pressure On The Fatigue Crack Growth Behavior Of Pressure Vessel Steels, Ashok Saxena, Kip O. Findley

Mechanical Engineering Faculty Publications and Presentations

A phenomenological model for estimating the effects of load ratio R and hydrogen pressure P_H2 on the hydrogen-assisted fatigue crack growth rate (HA-FCGR) behavior in the transient and steady-state regimes of pressure vessel steels is described. The "transient regime" is identified with crack growth within a severely embrittled zone of intense plasticity at the crack tip. The "steady-state" behavior is associated with the crack growing into a region of comparatively lower hydrogen concentration located further away from the crack tip. The model treats the effects of R and P_H2 as being functionally separable. In the transient …

Modeling Study Of Si3N4 Waveguides On A Sapphire Platform For Photonic Integration Applications, Diandian Zhang, Shui-Qing Yu, Gregory J. Salamo, Richard A. Soref, Wei Du

Electrical Engineering and Computer Science Faculty Publications and Presentations

Sapphire has various applications in photonics due to its broadband transparency, high-contrast index, and chemical and physical stability. Photonics integration on the sapphire platform has been proposed, along with potentially high-performance lasers made of group III–V materials. In parallel with developing active devices for photonics integration applications, in this work, silicon nitride optical waveguides on a sapphire substrate were analyzed using the commercial software Comsol Multiphysics in a spectral window of 800~2400 nm, covering the operating wavelengths of III–V lasers, which could be monolithically or hybridly integrated on the same substrate. A high confinement factor of ~90% near the single-mode …