Development of a Simplistic Method for Processing Intermetallic Sheet Materials Using Cold Roll Bonding and Reaction Annealing (National Science Foundation)
The processing and fabrication of intermetallic compounds and layered composites are inordinately expensive because of the sophisticated methodologies associated with existing processing techniques for these materials. The lack of breakthroughs in cost effective processing techniques are partially responsible for their lack of wide spread use in industry. This project investigates cold roll bonding followed by reaction annealing as a simple processing technique for the fabrication of intermetallic compounds and layered composites that are difficult, perhaps even impossible to process using conventional metal processing methods.
Fundamentals of Welding Intermetallic Compounds and Alloys (National Science Foundation)
In the overwhelming majority of engineering applications for intermetallic compounds are being considered, fusion welding is the primary form of joining. Sound (crack and void free) welds using the gas tungsten arc process with matching, or near matching, filler metal have been accomplished for several gamma-TiAl alloys. However, procedures for consistently producing crack-free autogenous (without filler metal) welds have not been achieved. This project couples computer modeling with actual welding to investigate the autogenous weldability of all intermetallic compounds applying gamma-TiAl
as the model material.
The Effect of Texture on the Weld Structure and Properties of Gamma-TiAl Sheet Material
This project investigates the microstructure and mechanical properties of welded gamma-TiAl sheet material. Gas tungsten arc welding both along and transverse to the direction of rolling is performed and the microhardness, tensile properties and microstructure of the welds are determined. It is the objective of this project to establish the weld structure-property relationship as a function of texture.
The Effect of Phosphorus on the Structure and Properties of Welded Inconel Alloy 718
For numerous years, phosphorus has been believed to have a detrimental effect on Ni-base alloy 718. However, studies have shown that P could actually have a positive effect. Although previous studies have investigated the effect of P on the mechanical properties of alloy 718, there has not been extensive work to investigate the effect after the material has been welded. The purpose of this study is to determine how the phosphorus content of alloy 718 affects the weld microstructure and properties.
Introducing Science Faculty from Historically Black Colleges and Universities (HBCU’s) to Materials Science and Engineering (National Science Foundation)
This workshop has been developed to introduce faculty and educators from all science disciplines to the field of materials science and engineering (MSE). The workshop format couples traditional and non-traditional classes with a combination of “hands on“ laboratory activities and tours of industrial materials facilities. It is the purpose of this workshop to provide faculty from HBCU’s with a thorough introduction to the materials science and engineering discipline.
Hardness Anisotropy in Single Crystals
The hardness of single crystals is highly anisotropic, that is it depends on the crystal plane which is measured and the orientation of the diamond indenter on that a crystal plane. Generally the hardness of a material in its single crystal form is only reported for different planes and directions for a single test load, however, the measured hardness is dependent on the indention test load applied during the measurement. This is known as the indentation size effect, or ISE. An interesting approach to gain further understanding of the interdependence of the hardness anisotropy and the indentation size effect is to analyze the related phenoma for single crystal materials. The goal of this research is to gain a further understanding of the phenomena.
The Brittle to Ductile Transition in Ceramics
The transition from brittle to ductile behavior of crystalline ceramics has been of fundamental interest for many decades, but is hardly understood for even the simplest ceramic structures. An interesting candidate material to study is calcium fluoride, which has five independent slip systems at elevated temperatures, >300 C, and is readily available in single crystal form. The toughness of this material can be ascertained by measuring precracked specimens as a function of temperature and strain rate. The resulting toughness trends can be applied to gain a further understanding of the brittle to ductile transition.
Oxidation of MgO-C Refractories
Utilization of composite MgO-C refractories has significantly prolonged their campaign life in BOF furnaces. A major contributing factor to this increased longevity is the utilization of metal powder additives, including Al, Si and Mg. These are often referred to as antioxidants for they reduce the rate of oxidation of the C in the refractories. Unfortunately, the use of these metal powder additions complicates the oxidation behavior of the refractory and the kinetics of the phenomenon is not at all well understood. The oxidation process may be understood by the development of a series of time/temperature exposures of the refractories. This research involves she development of that series and its analysis.
Microstructural Evolution and Grain Growth in Varistor Zinc Oxide Ceramics
The major material for the manufacture of commercial varistors is zinc oxide. These electronic devices are used in many applications for the protection against power surges, including line fluctuations and lightning strikes. The manufacturing process is a power processing one that involves the sintering in the presence of a liquid phase rich in bismuth oxide. The current voltage characteristics of the zinc oxide devices are the consequence of the grain boundary action of the material and thus are directly related to the grain size of the final product. Understanding of the grain growth characteristics of zinc oxide is a vital factor to the production of these devices.
- Electromagnetic processing of Metals including induction heating of semi-solid Al billets, containerless Induction melting of Al-Li and Ni-based alloys, electromagnetic filtration of aluminum, solidification processing of Zn-Bi hyper-monotectic alloys in an applied EM force field.
- Mathematical and physical modeling of material processing operations including electromagnetic stirring in continuous casting of steel, electromagnetic casting of aluminum, inclusion removal in molten metals processing systems, TGA welding processes, thermal plasma spraying and synthesis of materials.
- Magnetohydrodynamics: electromagnetic field interactions with suspended particles in crossed electric and magnetic fields.
- Computational electromagnetics and fluid dynamics: development of efficient algorithms for solving coupled electromagnetic, fluid flow and heat transfer equations.
Please refer to the Website: http://bama.ua.edu/~sgupta/
Please refer to the Website: http://www.bama.ua.edu/~rreddy/research.htm
Professor Thompson’s research is in the thermodynamics and mechanisms of phase transformations and their behavior on microstructure. His research utilized a variety of state-of-the-art analytical microscopes that characterize materials from the atomic to micron-length scales. For more information, please visit his research website.
- Processing of alloys,intermetallics,and composites
Casting and solidification,castability,porosity,hot-tearing,characterization of cast microstructures vs. properties; Deformation processing.
- Modeling of solidification processes
Heat,fluid,mass,phase change,and stress models; Distortion,microstructure and defect prediction.
- Modeling of heat treatment,microstructures, and properties of castings.
- Bonding of dissimilar materials,Coatings for die life extension.
Amime-Quinone Polymers - A New Class of Corrosion Resistant Coatings
(UA Center for Materials for Information Technology)
In research performed at UA, a new polymer (AQ) has been shown to significantly improve the corrosion resistance of sub-micron sized Fe particles in an aggressive environment (pH 2). Similar improvement has also been found for Fe plates coated with the same polymer. These polymers show much promise for applications ranging from the magnetic tape industry to inhibitors or coatings for electronic materials and devices. The primary objectives of this research program are aimed at a fundamental understanding of the nature of the AQ polymer/metal interface and the mechanism by which the polymer improves corrosion resistance. Research in our laboratories has shown that although the AQ polymer coatings absorb water, they still inhibit the formation of a metal/electrolyte interface even after 150 days of exposure to 0.1 M NaCl. Our goal is to understand the nature of the bond between polymer and metal through two research thrusts. Interfacial properties are being examined by various techniques including typical DC electrochemical methods, AC impedance methods, FTIR, ESCA and Auger. This research is a collaborative effort with Drs. David Nikles and Shane Street in the Dept. of Chemistry.
Electrochemical Research in Permanent Magnets (Magnequench, Inc.)
Many Rare Earth-Transition Metal (RE-TM) materials can absorb significant quantities of hydrogen. In the case of LaNi5 the quantity of absorbed hydrogen is so large that it forms the basis for a new generation of electric (hydrogen storage) batteries with a significantly higher ratio of engergy capacity to weight than is currently available. Nd2Fe14B materials are becoming increasingly common in many small electric motors, generators, computer hard drives, etc. Unfortunately Nd2Fe14B materials exhibit relatively poor corrosion resistance. Previous research in our laboratories has shown that NdFeB materials also absorb hydrogen, though to a lesser extent. The composition of these materials is constantly evolving and small amounts of Ti, Co, Al, Dy, Ga, B, C, etc., can significantly affect the magnetic properties and the corrosion behavior. The processing steps that the material is subjected to also influences the structure and properties, including corrosion. Investigations in our laboratory have provided some of the few direct, electrochemical studies of the corrosion behavior of this class of materials. Results have shown that the addition of selected alloying elements can significantly improve corrosion resistance, and that the absorption of hydrogen is often synonymous with increased corrosion rates. Recent results have shown that TiC additions in conjunction with rapid solidification techniques can decrease corrosion rates by a factor of two or three. Similarly, die upset and hot pressed magnets show improved corrosion resistance compared with sintered magnets.
Please refer to the Website: http://bama.ua.edu/~mweaver/research.htm
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