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A Study of Mechanisms to Engineer Fine Scale Alpha Phase Precipitation in Beta Titanium Alloy, Beta 21S

Description: Metastable b-Ti alloys are titanium alloys with sufficient b stabilizer alloying additions such that it's possible to retain single b phase at room temperature. These alloys are of great advantage compared to a/b alloys since they are easily cold rolled, strip produced and can attain excellent mechanical properties upon age hardening. Beta 21S, a relatively new b titanium alloy in addition to these general advantages is known to possess excellent oxidation and corrosion resistance at elevated t… more
Date: August 2013
Creator: Behera, Amit Kishan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Laser Deposition, Heat-treatment, and Characterization of the Binary Ti-xmn System

Description: The present research seeks to characterization of an additively manufactured and heat-treated Ti-xMn gradient alloy, a binary system that has largely been unexplored. In order to rapidly assess this binary system, compositionally graded Ti-xMn (0<x<15 wt%) specimens were fabricated using the LENS (Laser Engineered Net Shaping) and were subsequently heat-treated and characterized using a wide range of techniques. Microstructural changes with respect to the change in thermal treatments, hardness … more
Date: August 2013
Creator: Avasarala, Chandana
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Dislocation Dynamics Simulations of Plasticity in Cu Thin Films

Description: Strong size effects in plastic deformation of thin films have been experimentally observed, indicating non-traditional deformation mechanisms. These observations require improved understanding of the behavior of dislocation in small size materials, as they are the primary plastic deformation carrier. Dislocation dynamics (DD) is a computational method that is capable of directly simulating the motion and interaction of dislocations in crystalline materials. This provides a convenient approach t… more
Date: August 2013
Creator: Wu, Han
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Complementary scientific techniques for the study of Mesoamerican greenstone objects

Description: In this article the authors examine a set of Mesoamerican jade and greenstone objects from the collection at the Dallas Museum of Art using multiple non-destructive techniques, including scanning electron microscopy with energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction and handheld X-ray fluorescence spectroscopy. The authors present the results from their study and discuss them in their archaeological and historical context.
Date: February 5, 2024
Creator: Knight, Willow; Gantz, Faith; Carl, Matthew; Young, Marcus L.; Kovacevich, Brigitte; Crawford, Dawn et al.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Mist and Microstructure Characterization in End Milling Aisi 1018 Steel Using Microlubrication

Description: Flood cooling is primarily used to cool and lubricate the cutting tool and workpiece interface during a machining process. But the adverse health effects caused by the use of flood coolants are drawing manufacturers' attention to develop methods for controlling occupational exposure to cutting fluids. Microlubrication serves as an alternative to flood cooling by reducing the volume of cutting fluid used in the machining process. Microlubrication minimizes the exposure of metal working fluids to… more
Date: August 2013
Creator: Shaikh, Vasim
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Growth Mechanisms of Nano-to Micro-Sized Lead Sulfate Particles

Description: This article aims to determine the nucleation and growth mechanisms of PbSO4 nanoparticles in various solutions to potentially reduce or control the buildup of PbSO4 on battery electrodes over time.
Date: April 14, 2021
Creator: Wall, Michael T.; Smith, Jesse D.; Carl, Matthew; Young, Marcus L.; Hesterberg, Travis & Ellis, Tim
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

A novel nano-particle strengthened titanium alloy with exceptional specific strength

Description: This article microstructurally tailors an exceptionally high-strength titanium alloy, Ti-6Al-2Sn-4Zr-6Mo (Ti6246) through friction stir processing (FSP) in order to provide enhanced weight savings and improved fuel efficiency. The specific strength attained in one of the conditions is close to 450 MPa m³/mg, which is about 22% to 85% greater than any commercially available metallic material. This novel nano particle strengthened Ti alloy is a potential replacement for many structural alloys, en… more
Date: August 13, 2019
Creator: Dutt, Aniket K.; Gwalani, Bharat; Tungala, Vedavyas; Carl, Matthew; Mishra, Rajiv; Tamirisakandala, Sesh A. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering

Development and Thermo-Mechanical Testing of Low Hysteresis Shape Memory Alloy for Satellite Actuators

Description: Shape memory alloys (SMAs) have gained much attention as a powerful source of actuation due to their improved performance, reduced size, and reduced complexity between components as well as having a high work output density. Their primary mechanism of actuation relies on a non-diffusional cyclic phase transformation from martensite to austenite, where the amount of thermal energy needed per cycle is directly associated with the hysteresis width between the austenite final and martensite final t… more
Date: December 2022
Creator: Montagnoli, Andre Luiz
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Characterization and Chemical Analysis of Fundamental Components for Lead Acid Batteries

Description: Although markets for alternative batteries, such as Li-ion, are growing, Pb-alloy batteries still dominate the market due to their low cost and good functionality. Even though these Pb-alloy batteries have been around since their discovery in 1859, little research involving advanced characterization techniques, such as synchrotron radiation X-ray diffraction (SR-XRD) and transmission electron diffraction (TEM) have been performed on Pb-alloys and sulfation, a failure mode in lead acid batteries… more
Date: May 2022
Creator: Wall, Michael T
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Design and Performance of Metal Matrix Composite Composed of Porous Boron Carbide Created by Magnetic Field-Assisted Freeze Casting Infiltrated with Aluminum (A356)

Description: Magnetic field-assisted freeze-casting was used to create porous B4C ceramic preforms. An optimum slurry consisted of a mixture of B4C powders with 6 wt.% Er2O3 powder in an H2O-PVA solution and was cooled at a rate of 1 °C/min from room temperature to -30 °C resulting in porous green state ceramic preform with vertical channels. The Er2O3 powder was added to improve the magnetic response of the slurry. The preform was then sublimated to remove H2O and then sintered. The sintered ceramic prefor… more
Date: May 2022
Creator: Gamboa, Gerardo
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Developing Modern Atom Probe Tomography for Nonmetals

Description: Atom probe tomography as a 3D atomic-scale characterization tool has seen considerable development in the past decade, both in systems improvement and theoretical understanding. However, the time and expertise required from the outset of experimentation to analyzed results is highly asymmetric between metals and nonmetals. For complex oxides, this difficulty can be exemplified by GdBa2Cu3O7-x based high-temperature superconducting coated conductors. The objective of this dissertation is to furt… more
Date: December 2022
Creator: Smith, Jesse Daniel
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Advanced Cathodes for High Energy Density Lithium Sulfur Battery

Description: A systematic development of 2D alloy catalyst with synergistic performance of high lithium polysulfide (LiPS) binding energy and efficient Li+ ion/electron conduction is presented. The first section of work found that Li+ ions can flow through the percolated ion transport pathway in polycrystalline MoS2, while Na+ and K+ ions can easily flow through the percolated 1D ion channel near the grain boundaries. An unusually high ionic conductivity of extrinsic Li+, Na+, and K+ ions in 2D MoS2 film ex… more
Date: December 2021
Creator: Bhoyate, Sanket
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Investigation of Porous Ceramic Structure by Freeze-Casting

Description: The design and fabrication of porous ceramic materials with anisotropic properties has, in recent years, gained popularity due to their potential application in various areas that include medical, energy, defense, space, and aerospace. Freeze-casting is an effective, low-cost, and safe method as a wet shaping technique to create these structures. To control the morphology of these materials, many critical factors were found to play an important role. In this dissertation, the processing paramet… more
Date: May 2021
Creator: Bakkar, Said Adnan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Alloy Design, Processing and Deformation Behavior of Metastable High Entropy Alloys

Description: This dissertation presents an assortment of research aimed at understanding the composition-dependence of deformation behavior and the response to thermomechanical processing, to enable efficient design and processing of low stacking fault energy (SFE) high entropy alloy (HEAs). The deformation behavior and SFE of four low SFE HEAs were predicted and experimentally verified using electron microscopy and in-situ neutron diffraction. A new approach of employing a minimization function to refine … more
Date: May 2021
Creator: Frank, Michael (Materials science researcher)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Processing and Shape-Setting of Shape Memory Alloys for Small Satellite Antennas

Description: In this study, four different NiTi-based shape memory alloys (SMAs) compositions were processed, shape-set, and characterized to evaluate their effectiveness as SMA actuation component for satellite antennas. Three of the compositions were commercially available NiTi wires (90°C Flexinol® actuator NiTi wire and Confluent ADB SE508 NiTi wire), NiTi SM495 plates (ATI Specialty Alloys and Components) and the other composition was in house lab-produced NiTiCu plate. Different shape-setting techniqu… more
Date: December 2022
Creator: Al Jabri, Nehal Ahmed Mubarak
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

A Study on High Pressure-Induced Phase Transformations of a Metastable Complex Concentrated Alloy System with Varying Amounts of Copper

Description: Complex concentrated alloys (CCAs) offer the unique ability to tune composition and microstructure to achieve a wide range of mechanical performance. Recently, the development of metastable CCAs has led to the creation of transformation-induced plasticity (TRIP) CCAs. Similar to TRIP steels, TRIP CCAs are more effective at absorbing high strain rate loads when TRIP is activated during the loading process. The objective of our study is to investigate the effect of copper on the critical pressure… more
Date: May 2022
Creator: Reynolds, Christopher
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Effects of Surface Texture and Porosity on the Corrosion Behavior and Biocompatibility of Pure Zinc Biomaterials for Orthopedic Applications

Description: In this dissertation, small and large NaCl particle-derived surfaces (Ra > 40 microns) were generated on 2D Zn materials, and the surfaces were carefully studied concerning topography, corrosion behavior, and bone cell compatibility. Increases in surface roughness accelerated the corrosion rate, and cell viability was maintained. This method was then extended to 3D porous scaffolds prepared by a hybrid AM/casting technique. The scaffolds displayed a near-net shape, an interconnected pore struct… more
Date: May 2021
Creator: Cockerill, Irsalan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Silver Tantalate: a High Temperature Tribological Investigation

Description: As technology advances, mechanical and electrical systems are subjugated to intense temperature fluctuations through their service life. Designing coatings that operate in extreme temperatures is, therefore, a continuing challenge within the tribology community. Silver tantalate was chosen for investigation at the atomic level, the physical and chemical properties that influence the thermal, mechanical, and tribological behavior for moving assemblies in high temperature tribological application… more
Date: December 2014
Creator: Stone, D’Arcy S.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Thermo-Mechanical Processing and Advanced Charecterization of NiTi and NiTiHf Shape Memory Alloys

Description: Shape memory alloys (SMAs) represent a revolutionary class of active materials that can spontaneously generate strain based on an environmental input, such as temperature or stress. SMAs can provide potential solutions to many of today's engineering problems due to their compact form, high energy densities, and multifunctional capabilities. While many applications in the biomedical, aerospace, automotive, and defense industries have already been investigated and realized for nickel-titanium (Ni… more
Date: May 2020
Creator: Ley, Nathan A
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Processing, Pre-Aging, and Aging of NiTi-Hf (15-20 at.%) High Temperature Shape Memory Alloy from Laboratory to Industrial Scale

Description: The overarching goal of this research was to generate a menu of shape memory alloys (SMAs) actuator materials capable of meeting the demands of aerospace applications. Material requirements were recognized to meet the demand for high temperature SMAs with actuating temperatures above 85 °C and provide material options capable of performing over 100K actuation cycles. The first study is a preliminary characterization for the down selection of Ni-rich NiTiHf15 compositions chosen for a more in-de… more
Date: December 2020
Creator: Gantz, Faith
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Alloy Development and High-Energy X-Ray Diffraction Studies of NiTiZr and NiTiHf High Temperature Shape Memory Alloys

Description: NiTi-based shape memory alloys (SMAs) offer a good combination of high-strength, ductility, corrosion resistance, and biocompatibility that has served them well and attracted the attention of many researchers and industries. The alloys unique thermo-mechanical ability to recover their initial shape after relatively large deformations by heating or upon unloading due to a characteristic reversible phase transformation makes them useful as damping devices, solid state actuators, couplings, etc. H… more
Date: May 2018
Creator: Carl, Matthew A
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Processing of NiTi Shape Memory Alloys through Low Pressure and Low Temperature Hydrogen Charging

Description: Many industries including the medical, aerospace, and automobile industries have increasingly adopted the use of shape memory alloys (SMAs) for a plethora of applications due to their unique thermomechanical properties. From the commercially available SMAs in the market, binary NiTi SMAs have shown the most desirable properties. However, SMA properties can be significantly affected by the fabrication process. One of the most familiar applications of NiTi SMAs is in the design of actuating devic… more
Date: May 2018
Creator: Briseno Murguia, Silvia
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Process Improvement of Surface Preparation of Structuraly Bonded Helicopter Detail Parts

Description: The objective of this study was to increase the bond strength at the surface interface of a thin stainless-steel panel for structural bonding on a helicopter. To achieve this objective, six activation methods for applying the coating to the panel in the surface preparation process are presented and explored. Adhesion and roughness tests were conducted to determine which method consistently initiates the etch and improves the bond at the surface. Based on the test results, three methods proved t… more
Date: December 2018
Creator: Tafoya, Keirsten Breann
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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