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Crystallization and Lithium Ion Diffusion Mechanism in the Lithium-Aluminum-Germanium-Phosphate Glass-Ceramic Solid Electrolytes

Description: NASCION-type lithium-aluminum-germanium-phosphate (LAGP) glass-ceramic is one of the most promising solid electrolyte (SEs) material for the next generation Li-ion battery. Based on the crystallization of glass-ceramic material, the two-step heat treatment was designed to control the crystallization of Li-ion conducting crystal in the glass matrix. The results show that the LAGP crystal is preferred to internally crystalize, Tg + 60%∆T is the nucleation temperature that provides the highest ion… more
Date: May 2021
Creator: Kuo, Po Hsuen
Partner: UNT Libraries

Photophysical Interactions in Vapor Synthesized and Mechanically Exfoliated Two-Dimensional Conducting Crystallites for Quantum and Optical Sensing

Description: In the first study, superconducting 2D NbSe₂ was examined towards its prototypical demonstration as a transition-edge sensor, where photoexcitation caused a thermodynamic phase transition in NbSe₂ from the superconducting state to the normal state. The efficacy of the optical absorption was found to depend on the wavelength of the incoming radiation used, which ranged from the ultra-violet (405 nm), visible (660 nm), to the infrared (1060 nm). In the second case involving WSe₂, the UV-ozone tr… more
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Date: August 2022
Creator: Jayanand, Kishan
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
Partner: UNT Libraries

Microstructure Evolution and Mechanical Response of Material by Friction Stir Processing and Modeling

Description: In this study, we have investigated the relationship between the process-microstructure to predict and modify the material's properties. Understanding these relationships allows the identification and correction of processing deficiencies when the desired properties are not achieved, depending on the microstructure. Hence, the co-relation between process-microstructure-properties helped reduce the number of experiments, materials & tool costs and saved much time. In the case of high entropy all… more
Date: August 2022
Creator: Gupta, Sanya
Partner: UNT Libraries

Processing-Structure-Property Correlation for Additively Manufactured Metastable High Entropy Alloy

Description: In the present study both fusion based - laser powder bed fusion (LPBF), and solid state - additive friction stir deposition (AFSD) additive manufacturing processes were employed for the manufacturing of a metastable high entropy alloy (HEA), Fe40Mn20Co20Cr15Si5 (CS-HEA). A processing window was developed for the LPBF and AFSD processings of CS-HEA. In case of LPBF, formation of solidification related defects such as lack of fusion pores (for energy density ≤ 31.24 J/mm3) and keyhole pores (for… more
Date: August 2022
Creator: Agrawal, Priyanshi
Partner: UNT Libraries
open access

In-situ Analysis of the Evolution of Surfaces and Interfaces under Applied Coupled Stresses

Description: To study the effect of the substrate support on the nanoscale contact, three different regimes, i.e., graphene on rigid (ultra-crystalline diamond) and on elastic (Polydimethylsiloxane) supports and free-standing graphene, were considered. The contribution of the graphene support to the mechanical and electrical characteristics of the graphene/metal contact was studied using the conductive atomic force microscopy (AFM) technique.The results revealed that the electrical conductivity of the graph… more
Date: August 2020
Creator: Lee, Ji Hyung
Partner: UNT Libraries

Tribo-Corrosion of High Entropy Alloys

Description: In this dissertation, tribo-corrosion behavior of several single-phase and multi-phase high entropy alloys were investigated. Tribo-corrosion of body centered cubic MoNbTaTiZr high entropy alloy in simulated physiological environment showed very low friction coefficient (~ 0.04), low wear rate (~ 10-8 mm3/Nm), body-temperature assisted passivation, and excellent biocompatibility with respect to stem cells and bone forming osteoblast cells. Tribo-corrosion resistance was evaluated for additively… more
Date: December 2020
Creator: Shittu, Jibril
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
Partner: UNT Libraries

Materials Approaches for Transparent Electronics

Description: This dissertation tested the hypothesis that energy transferred from a plasma or plume can be used to optimize the structure, chemistry, topography, optical and electrical properties of pulsed laser deposited and sputtered thin-films of ZnO, a-BOxNy, and few layer 2H-WS2 for transparent electronics devices fabricated without substrate heating or with low substrate heating. Thus, the approach would be compatible with low-temperature, flexible/bendable substrates. Proof of this concept was demons… more
Date: December 2021
Creator: Iheomamere, Chukwudi E.
Partner: UNT Libraries
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