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Full-Text Articles in Materials Science and Engineering

Microstructural Characterization And Analysis Of Laser-Powder Bed Fusion Grcop-84 By Metallurgical And Neutron Scattering Methods, Robert Minneci May 2021

Microstructural Characterization And Analysis Of Laser-Powder Bed Fusion Grcop-84 By Metallurgical And Neutron Scattering Methods, Robert Minneci

Doctoral Dissertations

GRCop-84 or Cu-8Cr-4Nb (atomic %) is a structural high-heat-flux Cu alloy that is dispersion strengthened by C15 Laves Cr2Nb [Niobium Chromide] that has seen significant development with laser additive manufacturing (AM), specifically laser-powder bed fusion (L-PBF) in recent years. A review of the development, properties, and performance of GRCop alloys has been conducted and provides pertinent background. The body of research provides fundamental understanding regarding microstructure evolution and phase interaction of GRCop-84 through characterization by neutron and X-ray scattering and metallographic techniques. This research is intended to bridge fundamental research of L-PBF, Cu alloys, structural thermal conductors, and …


Characterizing Local Order And Physical Properties Of Rare Earth Complex Oxides, Thomas Jacob Shamblin Aug 2016

Characterizing Local Order And Physical Properties Of Rare Earth Complex Oxides, Thomas Jacob Shamblin

Doctoral Dissertations

With more than 500 compositions, materials possessing the pyrochlore structure have a myriad of technological applications and physical phenomena. Three of the most noteworthy properties are the structure’s ability to resist amorphization making it a possible host matrix for spent nuclear fuel, its exotic magnetic properties arising from geometric frustration, and fast ionic conductivity for solid-oxide fuel cell applications. This work focuses on these three aspects of the pyrochlore’s many potential uses. Structural characterization revealed that pyrochlore-type oxides have a tendency to disorder from a high symmetry cubic structure to a lower symmetry orthorhombic arrangement in response to a variety …


Temperature-Dependent Structures And Atomic Mixing Behaviors In High-Entropy Alloys, Louis J. Santodonato May 2016

Temperature-Dependent Structures And Atomic Mixing Behaviors In High-Entropy Alloys, Louis J. Santodonato

Doctoral Dissertations

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 …


Disorder In Mg1-Xnixal2o4 Spinel And Its Impact On The Response To Swift Heavy Ion Irradiation, Brandon Alexander Perlov Aug 2015

Disorder In Mg1-Xnixal2o4 Spinel And Its Impact On The Response To Swift Heavy Ion Irradiation, Brandon Alexander Perlov

Masters Theses

Spinels, which are currently used in optical applications, have many proposed functions in the nuclear industry, such as a nuclear waste form due to its radiation resistance. Disordering plays a key role in the response of spinel to a wide range of irradiation conditions. The first part of this research project was on characterizing the type and degree of disorder that can be induced by chemical substitution in the magnesium nickel aluminate spinel solid solution series (Mg(1-x)Ni(x)Al2O4). Neutron total scattering has been used to characterize the structure at both the cation and anion sublattices. High-resolution pair distribution function analysis was …


Structure And Dynamics Of High Temperature Superconductors, Jennifer Lynn Niedziela Dec 2012

Structure And Dynamics Of High Temperature Superconductors, Jennifer Lynn Niedziela

Doctoral Dissertations

High temperature superconductivity in iron based compounds has presented a series of complex problems to condensed matter physics since being discovered in 2008. The stalwart basis of condensed matter physics is the “strength in numbers" aspect of crystalline periodicity. Perfect crystalline periodicity has made possible the reduction of the questions of structural and electronic properties to single dimensions, increasing the tractability of these problems. Nevertheless, modern complex materials stretch these assumptions to their limits, and it is at this point where our work starts. Using neutron and x-ray scattering, we have conducted a series of studies on the structural disorder …