Materials Science and Engineering Commons^™

Comparative Evaluation Of Gating Systems In Femnal Castings, K. Balasubramanian, Laura Bartlett, M. Xu

Materials Science and Engineering Faculty Research & Creative Works

To understand the efficiency of gating systems, four systems, namely AFS styled pressurized system, AFS styled non-pressurized system, naturally pressurized system with a side riser and a naturally pressurized system with a top riser, were studied. The naturally pressurized systems were provided with overflows which collected the incoming metal swirl while the pressurized and non-pressurized systems had runner wells. Parameters like velocity of metal flow, air entrapment, microporosity and Niyama criterion were considered, and a design was developed with a common pouring basin using solidification software. Two molds were 3D printed using carbonitride sand, and steel of composition Fe-29Mn-8.2Al-0.91C-0.88Si-0.49Mo was …

Design Of Novel Gating Systems For Steel Castings, K. Balasubramanian, Laura Bartlett, M. Xu

Materials Science and Engineering Faculty Research & Creative Works

Gating systems play an important role in determining the quality and mechanical properties of castings. To understand the efficiency of gating systems, four systems, namely pressurized system, non-pressurized system, naturally pressurized system with a side riser and a naturally pressurized system with a top riser, were studied. The naturally pressurized systems were provided with overflows which collected the incoming metal swirl. Parameters like velocity of metal flow, air entrapment, microporosity and Niyama criterion were considered, and a design was developed with a common pouring basin. 8630 alloy was poured into two molds using a teapot ladle. The inclusion analysis revealed …

Overcoming Resolution Vs. Throughput Trade-Offs In Ceramic Material Extrusion Additive Manufacturing Via Viscoelastic Filament Stretching, Abid H. Rafi, David W. Lipke, Jeremy L. Watts, Gregory E. Hilmas, Ming C. Leu

Materials Science and Engineering Faculty Research & Creative Works

Fabricating large, monolithic ceramic parts using material-extrusion additive manufacturing remains challenging due to difficulty maintaining uniform moisture content during printing, which can lead to drying-induced defects such as warping and cracking, especially as part size and print time increase. Fabricated parts have trade-offs among print resolution, high throughput, and structural fidelity. Our study has shown that increasing the ratio of nozzle traverse speed vs. material extrusion speed increases filament stretching in viscoelastic ceramic paste, helping to overcome the trade-offs between resolution and throughput. Using aqueous ZrB2–SiC (70/30 vol.%) as a representative ultra-high temperature ceramic paste, rheological characterisation revealed viscoelastic yield-stress …

Microstructure And Properties Of Oxide Dispersion-Strengthened Alloys, Ertugrul Demir, Seung Min Ha, Anish Ranjan, Xingshuo Zhang, Aaron Penders, Mukesh Bachhav, Xiaochun Li, Lin Shao, Alexander Demblon, Haiming Wen, Enrique Lavernia

Materials Science and Engineering Faculty Research & Creative Works

Oxide dispersion-strengthened (ODS) alloys are a critical class of structural materials for extreme environments, owing to their unique combination of high-temperature strength, thermal stability, and radiation tolerance, enabled by a very high density of nanoscale oxide dispersoids. These features make ODS alloys attractive for advanced nuclear systems, aerospace applications, and other harsh-service conditions where conventional alloys rapidly degrade. Despite decades of development, key challenges remain in understanding how nanoscale oxides interact with matrix microstructures, alloy chemistry, and irradiation-induced defects to control macroscopic performance. This review provides a focused, mechanism-based synthesis of the microstructural features that govern the properties of ODS …

Evaluation Of A Novel Re-Crosslinkable Preformed Particle Gel For Conformance Control In Ultra-High Temperature Reservoirs, Yanbo Liu, Tao Song, Caleb Kwasi Darko, Thomas P. Schuman, Mingzhen Wei, Baojun Bai

Chemistry Faculty Research & Creative Works

Preferential fluid flow remains a major challenge in subsurface energy production and gas storage operations, resulting in excessive water production in mature oil fields, reduced heat extraction in geothermal reservoirs, and low sweep and storage efficiency in CO₂-EOR projects. Polymer gels are widely used to mitigate high-permeability channels; however, conventional systems exhibit limited plugging efficiency and short lifetimes in ultra-high-temperature reservoirs due to poor thermal stability. This study presents a novel ultra-high-temperature-resistant preformed particle gel (UHT-PPG) developed for conformance control in reservoirs with temperatures of 150–275 °C and severe super-K or channeling problems. The material was evaluated in …

Multiphysics Modeling Of Melt Pool Dynamics And Powder Bed Stability In Lpbf Of Inconel 718 For A Circular Cavity, Nayan Pundhir, Oluwapelumi O. Adejumo, Kumbla Chandrashekhara, Joseph W. Newkirk, Heath Misak, Cesar Ortiz Rios

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser powder bed fusion (LPBF) is a metal additive manufacturing process in which a concentrated laser beam selectively melts successive powder layers to fabricate components. Final part quality is highly sensitive to process parameters such as hatch spacing, powder bed density, laser power, and scanning speed. In this study, a computational fluid dynamics model employing discrete element method has been developed in FLOW-3D to simulate LPBF of Inconel 718. The modeled powder bed incorporates particle size distribution data obtained from scanning electron microscopy and is evaluated for single-layer, single-track deposition over a circular cavity. The model captured melt pool dynamics …

Evaluation Of Chromium-Crosslinked Amps-Hpam Copolymer Gels: Effects Of Key Parameters On Gelation Time And Strength, Maryam Sharifi Paroushi, Baojun Bai, Thomas P. Schuman, Yin Zhang, Mingzhen Wei

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Controlling CO₂ channeling in heterogeneous reservoirs remains a major challenge for both enhanced oil recovery (EOR) and secure geological storage. AMPS-HPAM copolymers exhibit high-temperature resistance and brine tolerance compared with conventional HPAM gels, making them well suited for the harsh environments associated with CO₂ injection. Chromium-based crosslinkers (CrAc and CrCl₃) were investigated because sulfonic acid groups in AMPS can coordinate with trivalent chromium ions, enabling dual ionic crosslinking and the formation of a robust gel network. While organic crosslinked AMPS-HPAM gels have been widely studied, the behavior of chromium-crosslinked AMPS-containing systems, particularly their gelation kinetics under …

Waveguide-Assisted Single-Mode Fiber Bragg Gratings In A Highly Multimode Coreless Fiber Via Femtosecond Laser Inscription For Extreme Temperature Quasi-Distributed Thermal Sensing, Farhan Mumtaz, Koustav Dey, Bohong Zhang, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This research reports a potential quasi-distributed thermal mapping optical sensing system for extreme temperatures, leveraging femtosecond (fs) laser inscribed single-mode fiber Bragg gratings (FBGs) and a waveguide within coreless, highly multimode optical fiber, resulting in a single-mode structure. Unlike doped single-mode fibers, coreless fibers composed of silica rods prevent issues associated with dopant migration and ensure data accuracy. The strategic placement of point-by-point FBGs in a cascaded formation on the fs-laser inscribed waveguide facilitates localized multipoint sensing. The long-term stability of the proposed waveguide-assisted FBG system was assessed over 24 hours at elevated temperatures (1000°C), showing no hysteresis during heating …

Distributed Temperature Sensing In The Spray-Cooled Shell Of A 150-Ton Dc Electric Arc Furnace Using Brillouin Optical Fiber Technology, Farhan Mumtaz, Yeshwanth Reddy Mekala, Koustav Dey, Rony Kumer Saha, Ogbole Collins Inalegwu, Manoj Kumar Pullagura, Bohong Zhang, Muhammad Roman, Nicholas Dionise, Zane Voss, Jeffrey D. Smith, Ronald J. O'Malley, Rex E. Gerald, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the deployment and validation of a Brillouin - distributed temperature sensing (DTS) system for real-time thermal monitoring of the spray-cooled upper shell of a 150-ton direct current Electric Arc Furnace (DC EAF) at Big River Steel Plant, Osceola, AR, USA. A four-channel Brillouin DTS system from OZ Optics was employed, with one active channel instrumented using an in-house-fabricated Brillouin scattering-depressed single-mode optical fiber (SMF28e+). The 60 m optical fiber sensor was fabricated, with 20 m allocated for thermal measurement and 40 m used as lead-in fiber to isolate the interrogator from the furnace environment. The fiber was …

Mitigating Hysteresis In Metal-Coated Fibers Via Optimized Thermal Treatment For Advanced Distributed High-Temperature Sensing Applications, Koustav Dey, Rony Kumer Saha, Bohong Zhang, S. Narasimman, Farhan Mumtaz, Jeffrey D. Smith, Rex E. Gerald, Ronald J. O'Malley, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Metal-coated optical fibers are widely employed in sensing applications owing to their superior mechanical strength and corrosion resistance. However, their calibration at elevated temperatures is hindered by hysteresis, manifested as discrepancies between heating and cooling cycles, primarily caused by residual strain from mismatched thermal expansion coefficients (TECs) between the metal coating and silica cladding. This research introduces an optimal heat treatment procedure aimed at minimizing the impact of the mismatch in TECs between the cladding and the coating materials that causes the residual strain in gold (Au) and copper (Cu) coated fibers for achieving reliable distributed high temperature sensing up …

Effect Of Process Parameters On Thermal Response Of An Oxy-Fuel Burner/Injector Panel In An Electric Arc Furnace Via Fiber Optic Sensors, Mobashir Ahmed, Rony Kumer Saha, Koustav Dey, Todd Sander, Jie Huang, Ronald J. O'Malley

Electrical and Computer Engineering Faculty Research & Creative Works

Modern oxy-fuel burner/injectors in electric arc furnaces (EAFs) play a critical role in scrap melting, liquid steel refining, and slag foaming. However, varying operational modes, combined with dynamic process conditions, such as arcing and slag behavior, can expose the injector panel surface to intense thermal conditions that can compromise efficiency and safety. Conventional monitoring techniques, including cooling water temperature measurements and thermocouples, fail to capture localized thermal anomalies due to their limited spatial resolution and susceptibility to electromagnetic interference. In this study, four high-resolution Rayleigh backscattering-based fiber optic sensors, interrogated via optical frequency domain reflectometry, were embedded in top and …

Investigations In Hydrogen Ironmaking, Joseph William Govro

Doctoral Dissertations

The purpose of this research is to contribute to the Grid Interactive Steelmaking with Hydrogen (GISH) project. This research investigates the viability of both producing and melting Direct-Reduced Iron (DRI) utilizing hydrogen. Conventional CO reduced DRI will be referred to as “C-DRI” and DRI produced using hydrogen gas will be referred to as “H-DRI”.

An H-DRI pilot plant was constructed in Golden Colorado. The pilot plant was commissioned and successfully operated four campaigns. Process improvements were made throughout the campaigns and the process was optimized. In addition to running the pilot plant in a pure hydrogen condition, the pilot plant …

Zirconium Carbide Based Materials For Extreme Aerospace Environments, Nathaniel Hyman Blatt

Doctoral Dissertations

This research focuses on the processing and properties of zirconium carbide-based materials to promote their use in extreme environment aerospace applications, including nuclear thermal propulsion and hyper sonics. Several carbide systems including ZrC, ZrC-Mo cermets, (Zr, Nb)C, and a high entropy carbide were developed. The ZrC-Mo cermet was studied extensively to understand the effect of starting carbide grain size on the final microstructure, composition, elastic moduli, hardness, fracture toughness, room and elevated temperature flexural strength, thermal diffusivity, electrical resistivity, thermal expansion coefficient, and thermal conductivity. It was shown that heat transport in the cermets was dominated by the ZrC phase …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

Strontium Titanate For Capacitor And Energy Storage Applications At Cryogenic Temperatures, Hung Trinh

Doctoral Dissertations

This study investigates the dielectric properties of single crystal and ceramic strontium titanate (SrTiO₃) for cryogenic capacitor applications from room temperature to 4 K. Permittivity (k) and loss tangent are dependent on temperature, frequency, mechanical stress, and applied DC electric field. Accordingly, the dielectric constant and loss tangent were measured at various frequencies and DC bias levels. Loss tangent data are also presented as equivalent series resistance (ESR). For single crystal SrTiO₃, an impurity level of ≈500 ppm barium resulted in an increase of the maximum permittivity to approximately 50,000 at 6 K. This relatively high …

Bond Behavior Of Full-Scale Beams Using Sustainable Self-Compacting Concrete, Hayder H. Alghazali, Atheer H.M. Algburi, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Sustainable concrete is a step towards greener and more eco-friendly concrete construction practices, helping to solve global environmental problems. The present study focuses on the bond behavior between steel reinforcement and greener self-compacting concrete, specifically sustainable self-compacting concrete (SUS-SCC). Three SUS-SCC mixtures with different fly ash (FA) to cement replacement levels of [50, 60, and 70% (by mass)] were developed. Twelve full-scale SUS-SCC beams with a cross-section of (305 x 57) mm and a total length of 3048 mm were cast and tested using a four-point load test setup. The effect of longitudinal and lateral steel reinforcement ratios in the …

Effects Of Wc Additions On The Phase Formation Of (Hf,Nb,Ta,Ti,Zr)C-(Hf,Nb,Ta,Ti,Zr)B2 High Entropy Dual Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

High entropy dual phase (Hf,Nb,Ta,Ti,Zr)C-(Hf,Nb,Ta,Ti,Zr)B2 ultra-high temperature ceramics were produced from powders synthesized by boro-carbothermal reduction. Systematic additions of 2.5 wt%, 5 wt%, and 10 wt% WC were incorporated after powder synthesis. Additions of 2.5 wt% and 5 wt% WC dissolved into the host ceramics, resulting in complete solid solution formation and nearly full densification. In contrast, a secondary monoboride phase evolved for the composition with 10 wt% WC, in addition to the main high entropy carbide and diboride phases. Thermodynamic analysis revealed that WB formation was favorable for WC additions in the presence of metal diborides at the sintering …

Thermal Properties Of High Entropy Dual Phase (Hf,Nb,Ta,Ti,Zr,)C-(Hf,Nb,Ta,Ti,Zr)B2 Ceramics: Comparison With The High Entropy Single-Phase Ceramics And The Effect Of Wc Additions, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

The heat capacity, thermal diffusivity and thermal conductivity of (Hf,Nb,Ta,Ti,Zr)C-(Hf,Nb,Ta,Ti,Zr)B₂ high entropy dual phase ceramics were evaluated from room temperature to 1800 °C and compared with the constituent high entropy single phase ceramics of the same nominal compositions. Thermal conductivity of the (Hf,Nb,Ta,Ti,Zr)C-(Hf,Nb,Ta,Ti,Zr)B₂ dual phase ceramic increased from 17.7 W m⁻¹ K⁻¹ at room temperature to 54 W m⁻¹ K⁻¹ at 1800 °C. The addition of WC to the dual phase ceramic reduced its thermal conductivity. For the addition of 5 wt% WC, room temperature thermal conductivity was 16.8 W m⁻¹ K^{−1 …}

Micro/Nanomechanical Properties Of Top-Seeded Melt Grown Ybco Single Crystals Determined Using Depth Sensing Indentation, Ugur Kolemen, Cafer Mert Yesilkanat, Fikret Yilmaz, Fatih Dogan, Orhan Uzun

Materials Science and Engineering Faculty Research & Creative Works

Mechanical properties of the bulk YBa2Cu3O7-x (YBCO) single crystal superconductor, prepared by using the Top Seeded Melt Growth (TSMG) method, were determined. Property measurements were conducted by the nanoindentation method under various loads and the micro indentation method at different temperatures. Hardness (H) and reduced elastic modulus (Er) values were calculated by using the Oliver–Pharr method. According to hf/h max values found from load- displacement curves, there is a sink in behavior around outer rim of the indents that was confirmed by atomic force microscopy (AFM) analysis. Nanoindentation analyses conducted on upper section, middle section and subsection revealed that all …

A Precipitation-Hardened High-Entropy Alloy With Excellent Mechanical Properties Additively Manufactured By In-Situ Alloying, Matthew Luebbe, Shahryar Mooraj, Jonathan Poplawsky, Hans Pommerenke, Wen Chen, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Studies on precipitation-hardened high-entropy alloys (PHEAs) have demonstrated high strength, good ductility, and thermal stability, making them excellent candidates for high-temperature structural applications such as nuclear reactors. However, many complex parts for those applications would need to be produced via additive manufacturing (AM), whose rapid cooling rates and multiple heating cycles could change the microstructure of the chosen alloys and accordingly their mechanical properties. A PHEA, (Fe0.3Ni0.3Mn0.3Cr0.1)88Ti4Al8, which was developed and produced via conventional manufacturing in our previous work with high strength but low ductility, was chosen to test the effects of AM on the microstructure and mechanical properties. Scanning …

Variable-Temperature Plasmonic High-Entropy Carbides, Simon Divilov, Sean D. Griesemer, Robert C. Koennecker, Michael J. Ammendola, Adam C. Zettel, Hagen Eckert, Jeffrey R. Shallenberger, Xiomara Campilongo, William G. Fahrenholtz, Arrigo Calzolari, Douglas E. Wolfe, Stefano Curtarolo

Materials Science and Engineering Faculty Research & Creative Works

Effective thermal management at variable and extreme temperatures face limitations for the development of novel energy and aerospace applications. Plasmonic approaches, shown to be capable of tailoring black-body emission, could be effective if materials with high-temperature and tunable plasmonic resonance were available. Here, we report a synergy between experimental and theoretical results proving that many high-entropy transition metal carbides, consisting of four or more metals at equal molar ratio, have plasmonic resonance at room, high (>1000∘C) and variable temperatures. We also found that these high-entropy carbides can be tuned and show considerable plasmonic thermal cycling stability. This paradigm-shift approach …

Effect Of Powder Recycling On Powder Characteristics And Mechanical Properties Of Materials Produced By Laser Powder Bed Fusion (Lpbf): A Review, Mihiretu Ganta, Marta Kurek, Arezoo Emdadi, Tadeusz Łagoda, Marek Pagáč

Materials Science and Engineering Faculty Research & Creative Works

As the Laser powder bed fusion (LPBF) process advances toward industrial-scale production, the sustainability of metal powder feedstocks has become a focal point of research. The powder recycling approach, while environmentally and economically favorable, results in a series of physicochemical variations that could compromise the part quality. The resulting variation in powder characteristics with powder recycling could affect the powder layer density and melt pool dynamics, resulting in defect formation and hindering the structural integrity of LPBFed parts. These alterations pose significant constraints to mechanical performance, particularly in fatigue-sensitive applications where even minor imperfections can substantially reduce service life. The …

Data Driven Design Of Ultra High Performance Concrete Prospects And Application, Bryan K. Aylas-Paredes, Taihao Han, Advaith Neithalath, Jie Huang, Ashutosh Goel, Aditya Kumar, Narayanan Neithalath

Electrical and Computer Engineering Faculty Research & Creative Works

Ultra-high-performance concrete (UHPC) is a specialized class of cementitious composites that is increasingly used in various applications, including bridge decks, connections between precast components, piers, columns, overlays, and the repair and strengthening of bridge elements. The mechanical and durability properties of UHPC are significantly influenced by factors such as low water-to-binder ratios, the inclusion of supplementary cementitious materials (SCMs), and fiber reinforcement. Machine learning (ML) has been employed to predict the performance of UHPC and optimize its mixture designs by using various raw materials. This study first provides a comprehensive review of ML applications in UHPC, focusing on predicting workability, …

Elucidating The Effects Of Water Activity On The Hydration Kinetics And Thermodynamics Of Ye’Elimite–Calcium Sulfate Hydrate Systems, Godwin I. Ogbuehi, Rupack R. Halder, Aditya Kumar, Gaurav Sant, Monday U. Okoronkwo

Materials Science and Engineering Faculty Research & Creative Works

Relative humidity and water activity (aH) reductions have been known to suppress the hydration of anhydrous cement clinker phases. However, the relationship between ye'elimite (C4A3$) hydration kinetics and water activity remain unclear. This study employs experimental and thermodynamic modeling approaches to investigate the influence of water activity on ye'elimite hydration in the "C4A3$ + water", and "C4A3$ + gypsum + water" systems. Experimental findings indicate that as water activity decreases, C4A3$ hydration diminishes until the reaction is brought to a halt at a threshold aH. The critical aHand corresponding solubility constant of C4A3$ (KC4A3S¯) estimated from thermodynamic analysis are 0.46 …

Effects Of Yttrium And Barium Trace Impurities On The Dielectric Properties Of  Srtio3 (111) Single Crystals At Cryogenic Temperatures, Hung Trinh, Alan Devoe, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Commercially available single crystals of (111) SrTiO₃ were found to contain impurities of varying amounts that strongly affected their dielectric performance at cryogenic temperatures. Three crystals with total impurities of 111, 126, and 625 ppm, primarily of barium and yttrium, were analyzed. Relative permittivity (εr) and loss tangent were investigated with high resolution as a function of temperature (4 K to 100 K), DC voltage (0 V/cm to 800 V/cm), and frequency (100 Hz to 1 MHz). An impurity level as low as ≈500 ppm barium resulted in an increase of the maximum permittivity (εm) to approximately 50,000 at …

Co2-Induced Changes In Rheology, Structural Evolution, And Particle Characteristics Of Cement Paste, Seongho Han, Tae Yong Shin, Seung Mo Kim, Jae Hong Kim, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The injection of carbon dioxide (CO₂) into cementitious systems has emerged as a promising approach to enhancing sustainability in concrete production. This study explores the impact of CO₂ injection on the rheological behavior, structural build-up, and particle size evolution of cement paste by systematically varying the water-to-cement ratio (w/c) (0.35, 0.4, and 0.5) and CO₂ concentration (0.06, 0.28, and 0.84 mol). Rheological analysis revealed a significant increase in initial yield stress with CO₂ injection. Using the Modified Bingham model, yield stress increased by 72 % and 150 % for 0.28- and 0.84-mol CO₂, …

Extraction Of Aluminum From Lunar Regolith Through Molten Salt Electrolysis, Jacob N. Ortega, Todd P. Sander, Jeffrey D. Smith, Fateme Rezaei, David J. Bayless, William Schonberg, Daniel S. Stutts, Frank D. Han

Materials Science and Engineering Faculty Research & Creative Works

This paper presents the methodology, development, and results of an end-to-end regolith-to-metal concept for producing aluminum in-situ on the lunar surface, namely, the Lunar In-Situ Aluminum Production through Molten Salt Electrolysis (LISAP-MSE) method. Using electrolytic reduction, aluminum oxide (i.e., alumina) can be reduced into aluminum and oxygen via electrolysis in a molten salt bath. A steady supply of hydrogen chloride could allow this in-situ resource utilization (ISRU) method to supply several necessary materials consumed in the electrolytic reduction step of the process to produce bulk aluminum metal, oxygen, water, and silica from anorthite abundant in lunar highland regions. In this …

Chemistry Of Inclusions By Size In Three Primary Copper Anodes, Charles Campbell, Michael Moats

Materials Science and Engineering Faculty Research & Creative Works

Three copper anodes from different commercial electro refineries were characterized to measure inclusion chemistry, size (diameter), and morphology. An automated scanning electron microscope (SEM) paired with energy-dispersive X-ray spectroscopy (EDS) was used to examine hundreds of inclusions near the mold and set sides of each anode. The investigation revealed that in the two anodes with less impurities (99.65% Cu and 99.75% Cu), many of the inclusions were Cu2O with an average diameter of 2 microns. The greater impurity anode (99.05% Cu, 4076 ppm Pb, 1939 ppm As, 635 ppm Bi) contained significant numbers of complex oxide inclusions, averaging 4.6 microns …

Tensile Performance Sensitivity To Variations Of Standard 17-4 Ph Heat Treatments On Lpbf-Produced Material, Ben Brown, Cory Read, Joseph Newkirk, Frank Liou

Materials Science and Engineering Faculty Research & Creative Works

Standard heat treatments for metals of a particular composition are typically designed with the assumption of a conventional starting microstructure, such as that produced by casting or wrought processing. When applied to metals fabricated by Laser Powder Bed Fusion (LPBF) metal additive manufacturing (AM), these heat treatments can produce inconsistent performance due to the unique as-built microstructures. This study investigates how modifications to standard heat treatments for 17-4 PH steel influence the microstructure and mechanical properties of LPBF-fabricated material. Specimens were produced and subjected to varying solutionizing and homogenizing treatments followed by standard aging treatments. Microstructures were characterized using optical …

Melting Behavior Of Direct Reduced Iron Pellets With Different Carbon Content In Molten Steel And Molten Slag, Fabian Andres Calderon Hurtado, Joseph Govro, Arezoo Emdadi, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

This study investigates the melting behavior of direct reduced iron (DRI) pellets in molten slag and steel baths, focusing on how the carbon content influences the melting rate through the stirring effects of gas evolution on heat transfer. A computational model using COMSOL Multiphysics 6.1 is developed to simulate the temperature profile at the pellet's core and the gas evolution resulting from the reaction between FeO and carbon within the pellet. The model is validated using experimental data from this study as well as literature on the DRI pellet–molten slag system. Results indicate that, despite the increased enthalpy demand associated …