Superalloys strengthened by γ′(L12)-precipitates in γ(f.c.c.)-matrix exhibit superior high temperature mechanical properties and environmental resistance over long periods of operation, making them ideal candidates for aerospace and energy conversion applications. The emerging class of superalloys based on Co-Al-W ternary system was identified with a melting temperature 50-100 ˚C higher than...
Dilute Al-Sc-Zr-Si-based aluminum alloys retain their strength for long periods of time at elevated temperatures due to a dispersion of nanometric, coherent, and coarsening-resistant Al3(Sc,Zr) (L12 structure) nanoprecipitates that are formed upon aging. These alloys are attractive for replacement of dense steels and costly Ti alloys in the 250–400 °C...
Water vapor condenses into liquid water when it encounters a cold surface. If the surface temperature is sufficiently low, freezing follows the condensation step, and the process is holistically referred to as condensation frosting. Both phase change processes are fundamental to many industries ranging from water harvesting, thermal management, solar...
The high-temperature oxidation/reduction behaviors of iron and its oxides are important to a variety of energy conversion and storage technologies, such as the solid-oxide iron-air battery and chemical looping combustion. The useful lifetime of iron redox materials is limited, however, by structural degradation arising from (i) sintering, accelerated by phase...
The effect of Alkali-Silica Reaction (ASR) on concrete mechanical behavior and the multi-physics considerations that come along are highly complex. Hydration and other chemical reactions occur at the micrometer scale. Hygro-thermal phenomena and concrete cracks due to ASR are typically studied at the meso-scale, i.e. at the aggregate level. At...
As conventional electronic materials approach the device scaling limits, new types of materials and structures have been examined for potential use in future electronic and optoelectronic applications including transistors, light emitting diodes, and solar cells. In recent years, atomically thin or two-dimensional (2D) transition metal dichalcogenide (TMD) materials have emerged...
The commercial success of personal computing has led to the rapid creation and proliferation of diverse electronic systems including desktops, laptops, tablets, mobile devices, and embedded systems. For the past five decades, silicon has served as the base material for computing electronics. However, with increasing demand for unconventional electronics (e.g.,...
The complex structure of typical heterogeneous catalysts, where nanoparticles of active material are dispersed onto the surface of a thermally stable support with a high surface area, complicates the understanding of how the support can affect the resulting catalyst structure and properties. Using well-faceted and shape-controlled oxides as supports would...
Early-stage oxidation and corrosion mechanisms of CoCrMo and NiCrMo alloys can be analyzed on the nanoscale by transmission electron microscopy. Both alloys are attractive for a broad array of applications such gas turbines and aircraft engine components as they are known for their excellent corrosion resistance and mechanical properties at...
Throughout history, the development of materials has relied heavily on the empirical judgment of scientists and engineers and on prolonged experiments proton to errors. Due to the complexity of material behavior, successful discovery of new candidates has been serendipitous, and down-selection of candidates remains a time-consuming process that requires repetitive...
Thermoelectric materials are of particular interest in a variety of fields because of their ability to directly convert heat to electricity (and vice versa), however, they struggle to gain widespread adoption because of their low efficiency. A common strategy in the field of thermoelectricity is to introduce material defects into...
High performance polymers and their composites have wide ranging application in advanced and emerging material systems. The macroscale performance of these advanced materials is often defined by interfaces that induce nanoscale changes in the microstructure or molecular conformations (termed the ‘interphase’) of the polymer. Atomic force microscopy (AFM) is an...
Given directives such as the UN Global Goals targeting sustainable development, the research presented herein makes but a small contribution to the advancement of alternative energy technologies. Nevertheless, the present work was largely motivated to address specific points of intrigue within the thermoelectrics community. The general principles demonstrated, however, may...
An extensive set of functional electronic properties depends on the electronic structure. These properties are directly connected to the reciprocal-space representation of electronic structure. However, there is a complementary, real-space perspective that is described by combinations of atomic orbitals. Atomic orbitals are the components of electronic structures, analogous to how...
Structural colors originate from the interaction between the incident light and a surface with periodic submicron structures. They enable the creation of a spectrum of nonfading colors, potentially replacing toxic metal oxides and conjugated organic pigments. However, significant challenges remain, including lack of contrast needed for the complete gamut of...
A series of theories and models are developed and used to investigate the growth of protective oxide films on metal and alloy surfaces for cases in which Wagner's classical model of oxidation does not hold. First, irreversible thermodynamics is applied to formulate a model for the outward growth of rocksalt...
Part I: Design of Photo-Responsive Molecules towards Biomedical ApplicationsThe use of light to control systems provides numerous advantages such as spatiotemporal precision, non-invasive penetration, and precise energy input. Specifically, molecules that undergo photoinduced cleavage, photoremovable protecting groups (PPGs) have emerged as an active area of research due to their broad...
A significant portion of material science research is concerned with understanding theway that defects affect the properties materials. In the field of thermoelectrics introducingor removing point (0D), dislocation (1D), grain boundary (2D), or precipitate (3D) defectsare popular methods for altering a materials thermoelectric efficiency. Herein I discussdifferent studies conducted during...
Transition metal oxides (TMOs) like perovskites are known to be versatile for functional properties such as ferroelectricity, magnetism, optical properties, and high-temperature superconductivity, because of their sensitive coupling between atomic structure and properties. By studying and understanding the fundamental structure-property relationships present in TMOs, it is possible to strategically engineer...
Supervised learning model is one of the most fundamental machine learning models. It can provide powerful capability of prediction by learning complex patterns hidden in many, sometimes thousands, predictors. It can also be used as a building block of other machine learning tasks, like unsupervised learning and reinforcement learning. Such...