Materials Engineering

Source: Faisal Alamgir, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA The imaging of microscopic structures of solid materials, and the analysis of the structural components imaged, is known as materialography. Qualitative information such as, for example, whether or not there is porosity in the material, what the size and shape distribution of the grains look like, or whether there is anisotropy to the microstructure can be directly observed. We will...

Source: Faisal Alamgir, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA The imaging of microscopic structures of solid materials, and the analysis of the structural components imaged, is known as materialography. Often, we would like to quantify the internal three-dimensional microstructure of a material using only the structural features evidenced by an exposed two-dimensional surface. While X-ray based tomographical methods can reveal buried...

Source: Faisal Alamgir, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA X-ray photoelectron spectroscopy (XPS) is a technique that measures the elemental composition, empirical formula, chemical state and electronic state of the elements that exist within a material. XPS spectra are obtained by irradiating a material with a beam of X-rays while simultaneously measuring the kinetic energy and number of electrons that escape from the top several...

Source: Faisal Alamgir, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA X-ray diffraction (XRD) is a technique used in materials science for determining the atomic and molecular structure of a material. This is done by irradiating a sample of the material with incident X-rays and then measuring the intensities and scattering angles of the X-rays that are scattered by the material. The intensity of the scattered X-rays are plotted as a function of the...

Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT As electron microscopes become more complex and widely used in research labs, it becomes more of a necessity to introduce their capabilities. Focused ion beam (FIB) is an instrument that can be employed in order to fabricate, trim, analyze and characterize materials on mico- and nano-scales in a wide variety of fields from nano-electronics to medicine. FIB...

Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT Directional solidification zone melting is a metallurgical process in which a narrow region of a crystal (usually in the form of bar) is melted. The furnace moves along the rod shape sample, meaning that the molten zone is moved along the crystal and the molten zone is moved from one end of the bar to the other. This mechanism is widely used in alloys, however...

Source: Danielle N. Beatty and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Differential scanning calorimetry (DSC) is an important measurement to characterize thermal properties of materials. DSC is used primarily to calculate the amount of heat stored in a material as it heats up (heat capacity) as well as the heat absorbed or released during chemical reactions or phase changes. However, measurement of this heat can also lead to...

Source: Elise S.D. Buki, Danielle N. Beatty, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT The laser flash method (LFA) is a technique used to measure thermal diffusivity, a material specific property. Thermal diffusivity (α) is the ratio of how much heat is conducted relative to how much heat is stored in a material. It is related to thermal conductivity (), how much heat is transferred through a material due to a temperature...

Source: Logan G. Kiefer, Andrew R. Falkowski, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a thin coating on an electrode. Other thin film deposition techniques include chemical vapor deposition (CVD), spin coating, dip coating, and sputter deposition among others. CVD uses a gas-phase precursor of the element to be...

Source: J. Jacob Chavez, Ryan T. Davis, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Thermal expansion is extremely important when considering which materials will be used in systems that experience fluctuations in temperature. A high or low thermal expansion in a material may or may not be desirable, depending on the application. For instance, in a common liquid thermometer, a material with a high thermal expansion would be...

Source: Kara Ingraham, Jared McCutchen, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Electrical resistance is the ability of an electrical circuit element to resist the flow of electricity. Resistance is defined by Ohm's Law:     (Equation 1) Where  is the voltage and  is the current. Ohm's law is useful for determining the resistance of ideal resistors. However, many circuit elements are more complex and can't be described by...

Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT Bones are composites, made of a ceramic matrix and polymer fiber reinforcements. The ceramic contributes compressive strength, and the polymer provides tensile and flexural strength. By combining ceramic and polymer materials in different amounts, the body can create unique materials tailored for a specific application. As biomedical engineers, having the ability...

Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT Alloys with grain size less than 100 nm are known as nanocrystaline alloys. Due to their enhanced physical and mechanical properties, there is an ever-increasing demand to employ them in various industries such as semiconductor, biosensors and aerospace.  To improve the processing and application of nanocrystalline alloys, it is necessary to develop close to 100%...

Source: Amber N. Barron, Ashlea Patterson, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Hydrogels are a versatile class of cross-linked polymers produced through relatively simple procedures and with generally inexpensive materials. They can be formed from solution and involve a polymer backbone formed from monomer reagents, an initiator which makes the polymer reactive and a crosslinking species which binds the polymer chains...