Interplay Of Quantum Size Effect, Anisotropy And Surface Stress Shapes The Instability Of Thin Metal Films, 2016 Western Kentucky University
Interplay Of Quantum Size Effect, Anisotropy And Surface Stress Shapes The Instability Of Thin Metal Films, Mikhail Khenner
Rapid Grain Boundary Mobility At Ambient Temperatures, 2016 Brigham Young University
Rapid Grain Boundary Mobility At Ambient Temperatures, Jarrod M. Lund, R Adam Bilodeau, Rebecca K. Kramer
The Summer Undergraduate Research Fellowship (SURF) Symposium
Understanding and measuring the influence of grain boundaries (planar defects in the crystalline structure of materials) and their motion has become a dominant aspect in materials research, with applications in additive manufacturing, fatigue prevention, and material modeling. However, modeling grain boundaries and grain boundary mobility (GBM) is difficult due to the high temperatures or external stresses, imaging solutions compatible with the material system, and long time-scales required to create measurable experimental results. In this paper, we introduce a novel material system that allows for easy and fast visualization of GBM. A drop of liquid metal eutectic gallium indium (eGaIn) placed ...
Fundamental Understanding Of Bond Formation During Solid State Welding Of Dissimilar Metals, 2016 University of Tennessee, Knoxville
Fundamental Understanding Of Bond Formation During Solid State Welding Of Dissimilar Metals, Niyanth S
Dissimilar metal welds are used in a wide range of applications to effect light weighting and for corrosion resistance. While fusion welding techniques are limited in their ability to fabricate dissimilar metal welds, solid state welding techniques are limited in their ability to fabricate complex geometries with dissimilar metal combinations. Hence alternative techniques need to be explored to fabricate complex geometries with dissimilar metals welds in the solid state. Ultrasonic additive manufacturing in a solid state additive manufacturing process that combines ultrasonic welding with mechanized tape layering to fabricate dissimilar metal welds in the solid state. Though extensive feasibility studies ...
Evaluation Of The Potential For Weld-Related Cracking In Cast 20cr-32ni-1nb Heat-Resistant Stainless Steel, 2016 University of Tennessee, Knoxville
Evaluation Of The Potential For Weld-Related Cracking In Cast 20cr-32ni-1nb Heat-Resistant Stainless Steel, John William Bohling
Steam reforming of hydrocarbons is an important process for the production of hydrogen for industrial needs, such as ammonia synthesis. Due to the high temperature conditions (700 °C–900 °C), reformer furnace components require materials with excellent creep properties and thus highly alloyed austenitic stainless steels are typically employed. For reformer outlet manifolds, a cast, heat-resistant stainless steel with the composition 20Cr-32Ni-1Nb (ASTM A351 Grade CT15C) is widely used. However, after service exposure this alloy exhibits problems with liquation cracking in the base metal heat-affected zone (HAZ) during repair welding. In the work presented herein, two heats of material from ...
Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, 2016 Boise State University
Thermoelectric Half-Heuslers: Synthesis, Processing, And Performance, Joseph Robert Croteau
Boise State University Theses and Dissertations
Thermoelectric half-Heusler compounds have potential to convert the heat wasted from industrial and transportation processes to useful electricity. Among the highest performing half-Heusler compounds are nano-structured bulk materials which have been arc-melted, pulverized into a nano-powder, and sintered by DC-hot press. High performing n- and p-type half-Heusler compounds with nominal composition of Hf0.25Zr0.75NiSn0.99Sb0.01 and Nb0.75Ti0.25FeSb, respectively, have been provided to us in both dense and powder form by our collaborators at the University of Houston. We consolidate these powders by SPS, refine these ...
Removal Of Mercury(Ii) From Aqueous Solutions By Adsorption On Poly(1-Amino-5-Chloroanthraquinone) Nanofibrils: Equilibrium, Kinetics, And Mechanism Studies, 2016 Kunming University of Science and Technology
Removal Of Mercury(Ii) From Aqueous Solutions By Adsorption On Poly(1-Amino-5-Chloroanthraquinone) Nanofibrils: Equilibrium, Kinetics, And Mechanism Studies, Shaojun Huang, Chengzhang Ma
Intrinsic Magnetic Properties In R(Fe1−Xcox)11tiz(R=Yand Ce;Z=H,C,And N), 2016 Ames Laboratory
Intrinsic Magnetic Properties In R(Fe1−Xcox)11tiz(R=Yand Ce;Z=H,C,And N), Liqin Ke, Duane D. Johnson
Ames Laboratory Publications
To guide improved properties coincident with reduction of critical materials in permanent magnets, we investigate via density functional theory (DFT) the intrinsic magnetic properties of a promising system, R(Fe1−xCox)11TiZ with R=Y, Ce and interstitial doping (Z=H,C,N). The magnetization M, Curie temperature TC, and magnetocrystalline anisotropy energy K calculated in local density approximation to DFT agree well with measurements. Site-resolved contributions to K reveal that all three Fe sublattices promote uniaxial anisotropy in YFe11Ti, while competing anisotropy contributions exist in YCo11Ti. As observed in experiments on R(Fe1−xCox)11Ti, we find a complex ...
Welding Procedure Qualification Of A36 Steel Plates Using The Gtaw And Gmaw Processes, 2016 California Polytechnic State University, San Luis Obispo
Welding Procedure Qualification Of A36 Steel Plates Using The Gtaw And Gmaw Processes, Brecken Deoilers, Neri Lupian, Regan Rumph
The purpose of this project was to qualify welding procedure specifications for the Las Positas College welding program using A36 steel in accordance with American Welding Society (AWS) D1.1, B4.0, and B2.1. Qualification was to be performed using both 1G (flat) and 3G (vertical) positions for Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW) processes. Required qualification procedures included two face and two root bend tests coupled with a visual inspection for cracks within the weld region greater than ⅛” long, along with two reduced section tensile tests to ensure the tensile strength exceeded ...
Effect Of Thermal Exposure On Tensile Strength And Microhardness Of Welded And Precipitation Hardened Rx82 Aluminum Alloy Extrusions In The T4 And T6 Conditions, 2016 California Polytechnic State University, San Luis Obispo
Effect Of Thermal Exposure On Tensile Strength And Microhardness Of Welded And Precipitation Hardened Rx82 Aluminum Alloy Extrusions In The T4 And T6 Conditions, Lucien Miller
This investigation is focused on the effect paint-bake cycles have on the tensile strength and microhardness of GMAW welded RX82 aluminum extrusions in T4 and T6 base conditions. To simulate the paint-bake cycle, T4 and T6 RX82 aluminum samples were GMAW welded and heat treated at 350°F, 390°F, and 425°F for durations of 30 minutes, 1.0 hour, and 2.0 hours, with five replicates for each treatment. Microhardness profiles of T4 samples treated at 350°F for 30 minutes and 1.0 hour display weld/HAZ HV values of 86.04 and 82.51 respectively, followed ...
Grain Orientation Effects On The Rotating-Bending Fatigue Properties Of Forged 7050-T7452 Aluminum Alloy, 2016 California Polytechnic State University, San Luis Obispo
Grain Orientation Effects On The Rotating-Bending Fatigue Properties Of Forged 7050-T7452 Aluminum Alloy, Matt Cristler, Jonas Zhang
In order to investigate the effects of grain orientation on the high cycle fatigue properties of 7050-T7452 aerospace grade aluminum, rotating-bending fatigue tests were performed on longitudinal (LG) and short transverse (ST) specimens taken from two sample sets (Method A and Method B) of open die forged 7050 aluminum. The fatigue specimens were machined to a 0.2" gage diameter and 4" length and subsequently hand polished to a mirror finish to minimize potential crack initiation sites. The tests were conducted on a Fatigue Dynamics RBF-300 HT tester in the fully reversed loading condition, with stress levels varying from 20 ...
Investigation Of Outlife Time On The Environmental Durability Of P2-Etched, Adhesively-Bonded Aluminum Alloys Using The Astm Wedge Test, 2016 California Polytechnic State University, San Luis Obispo
Investigation Of Outlife Time On The Environmental Durability Of P2-Etched, Adhesively-Bonded Aluminum Alloys Using The Astm Wedge Test, Daniel Gross, Corey Sutton
P2 etchant is an environmentally-friendly aluminum etchant which has the potential to replace the Forest Products Laboratory (FPL) etchant as the industry standard. Environmental durability of adhesively-bonded aluminum surfaces etched using a paste version of the P2 etchant were tested using the Boeing-developed wedge test (ASTM D3762 - 03(2010)). This project specifically aimed to examine the relationship between outlife time (the time between etching and adhering) and the ability of bonded aluminum samples to pass the wedge test. Two aluminum alloys, 2024-T3 and 7075-T6, were wedge tested and the etched surfaces examined with an atomic force microscope (AFM) and a ...
Effect Of Hydrogen Pick-Up And Release Behavior On The Tensile Properties Of Electroplated 4340m High-Strength Steel, 2016 California Polytechnic State University, San Luis Obispo
Effect Of Hydrogen Pick-Up And Release Behavior On The Tensile Properties Of Electroplated 4340m High-Strength Steel, Blake Daylor, Joshua Fisher, Alan Michelen Ruiz
Hydrogen embrittlement of high-strength steel (4340M) was quantified through tensile testing and fractography (SEM). Three types of samples were obtained: rotating beam fatigue specimens, round (notched) tensile specimens, and flat panel specimens. In addition, three different plating types were analyzed (Ni, Cr, Cd-Ti) with a set of samples that was shot peened and a set that was not. Since some of the samples went through a hydrogen relief bake, another factor in our experiment was the amount of time it took for the samples to reach the baking process after they were electroplated (bake delay). There were three levels of ...
Superalloy Metallurgy A Gleeble Study Of Environmental Fracture In Inconel 601, Alan C. Demmons
Master's Theses and Project Reports
At temperatures above 0.5 Tm and in aggressive atmospheres predicting alloy performance is particularly challenging. Nickel alloys used in regimes where microstructure and properties are altered dynamically present unique requirements. Exposure may alter properties with unexpected early failure. The Gleeble is a valuable tool for investigation and simulation of thermo-mechanical properties of an alloy in various regimes up to the threshold of melting. In this study, four regimes of temperature and strain rate were simulated in an argon atmosphere to both investigate and document normal and abnormal failure modes. Commercial Inconel 601 was tested in selected regimes and in ...
Combined Computational-Experimental Design Of High-Temperature, High-Intensity Permanent Magnetic Alloys With Minimal Addition Of Rare-Earth Elements, 2016 Florida International University
Combined Computational-Experimental Design Of High-Temperature, High-Intensity Permanent Magnetic Alloys With Minimal Addition Of Rare-Earth Elements, Rajesh Jha
FIU Electronic Theses and Dissertations
AlNiCo magnets are known for high-temperature stability and superior corrosion resistance and have been widely used for various applications. Reported magnetic energy density ((BH) max) for these magnets is around 10 MGOe. Theoretical calculations show that ((BH) max) of 20 MGOe is achievable which will be helpful in covering the gap between AlNiCo and Rare-Earth Elements (REE) based magnets. An extended family of AlNiCo alloys was studied in this dissertation that consists of eight elements, and hence it is important to determine composition-property relationship between each of the alloying elements and their influence on the bulk properties.
In the present ...
Coercivity Enhancement And Gamma Phase Avoidance Of Alnico Alloys, 2016 University of Nebraska-Lincoln
Coercivity Enhancement And Gamma Phase Avoidance Of Alnico Alloys, Li Zhang
Engineering Mechanics Dissertations & Theses
The promotion of social progress requires greater levels of energy efficiency, quality and productivity. However, these developments usually come at the cost of the environment. Green technologies such as electric vehicles, wind turbine and solar panels are ironically overshadowed by supply limitations and high prices of rare earth elements. Therefore, it is important to find alternative materials to replace those that contain critical elements. Alnico alloys show high magnetization, high Curie temperature (800°C) and good corrosion resistance, making it one of the best candidates to replace neodymium-based magnets used in electric vehicles.
In this thesis, methods controlling shape anisotropy ...
Manipulation Of Surface Plasmon Resonance In Metal And Alloy Thin Films Using Dielectric Media, 2016 Rose-Hulman Institute of Technology
Manipulation Of Surface Plasmon Resonance In Metal And Alloy Thin Films Using Dielectric Media, Benjamin Dubray Hall
Graduate Theses - Physics and Optical Engineering
Surface plasmon polaritons are coherent electron oscillations that propagate along an interface between a Drude metal and a dielectric medium. The excitation of polaritons is highly dependent on the dielectric properties of the metal, the thickness of the metal, and the optical properties of the dielectric material. First, plasmonic activity is assessed for several thicknesses of silver and nickel chromium under He-Ne incidence. Relationships between film thickness and metal dielectric function are explored in both cases. To manipulate the plasmonic activity at the silver surfaces, two methods are explored. Silver oxide was grown on the surface of the silver films ...
Temperature-Dependent Structures And Atomic Mixing Behaviors In High-Entropy Alloys, 2016 University of Tennessee - Knoxville
Temperature-Dependent Structures And Atomic Mixing Behaviors In High-Entropy Alloys, Louis J. Santodonato
The goal of the present dissertation is to advance the fundamental understanding of the atomic mixing behavior in a new class of alloys, known as high-entropy alloys (HEAs), and provide new methods to develop HEAs for practical applications. The HEA design strategy is based upon the influence of configurational entropy of mixing, which serves as a driving force for the formation of disordered solid-solution structures in certain alloys. In particular, alloys containing multiple elements have a tendency to form stable, disordered structures, sometimes with exceptional engineering properties. Despite the tendency toward structural disorder, HEAs usually have some degree of structural ...
Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, 2016 University of Tennessee - Knoxville
Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, Devin Alan Roberts
The disaster at the Fukushima Daiichi Nuclear Power Plant in March 2011 bought renewed focus to the issue of corrosion in nuclear fuel cladding applications. This thesis reports on the background behind these issues, the investigation strategy, and the analysis of experiments focused on mitigating oxidation of Zr-alloy fuel cladding. This thesis seeks to develop magnetron sputtered Ti-Al-C and Cr-Al-C coatings for Zr-alloy substrates and characterize the as-deposited and corroded samples.
Ti-Al-C and Cr-Al-C coatings were deposited onto ZIRLO, Si, and Al2O3 [Aluminum Oxide] substrates under various sputtering conditions. A combinatorial sputtering method was employed to refine ...
Electrochemical Characterization Of Xanthate Chemisorption On Copper And Enargite, 2016 Montana Tech of the University of Montana
Electrochemical Characterization Of Xanthate Chemisorption On Copper And Enargite, Tyler Broden
Graduate Theses & Non-Theses
The electrochemical reactions of copper and enargite (Cu3AsS4) were studied in the absence and presence of xanthate by cyclic voltammetry (C.V.) using electrodes fashioned from pure copper wire obtained from the Metallurgical and Materials Engineering Department, and an enargite mineral sample obtained from the Orphan Girl mine in Butte, MT. Voltammograms were produced in buffer solutions of pH values ranging from 7-12. Electrochemical reactions were discerned by comparing EH-pH diagrams calculated from thermodynamics using StabCal, a computer program developed by Dr. Huang at Montana Tech. The chemisorption of xanthate on the surface of copper ...
Vacuum Brazing Of Diamond To Tungsten Carbide, 2016 Montana Tech of the University of Montana
Vacuum Brazing Of Diamond To Tungsten Carbide, Zhiyong Yin
Graduate Theses & Non-Theses
Diamond tools are increasingly gaining importance as cutting and drilling materials for a wide variety of industrial applications. Polycrystalline diamond (PCD) is the main ultrahard material commercially used in the oil and gas drilling industry. In this study, a reactive brazing process was developed to join polycrystalline diamond (PCD) to WC-13 wt% Co, to form the cutter for fixed-cutter drill bit applications.
Most nonmetals including polycrystalline diamond are not wet by and cannot easily be joined with conventional brazing alloys due to their chemical stability. The experimental approach was first to analyze the effect of adding an active metal (Ti ...