Advanced Manufacturing, Processing, Characterization and Modeling of Functional Materials: Advanced Manufacturing, Processing, Characterization and Modeling of Functional Materials II
Program Organizers: Mohammad Elahinia, University of Toledo; Haluk Karaca, University of Kentucky; Reginald Hamilton, Pennsylvania State University; Mohammad J. Mahtabi; Narges Shayesteh Moghaddam, University of Texas at Arlington; Reza Rizvi, University of Toledo; Markus Chmielus, University of Pittsburgh; Hamdy Ibrahim, University Of Tennessee Chattanooga; Mohammadreza Nematollahi, University Of Toledo
Wednesday 2:00 PM
November 4, 2020
Room: Virtual Meeting Room 21
Location: MS&T Virtual
Session Chair: Haluk Karaca, University of Kentucky; Mohammadreza Nematollahi, University of Toledo
2:00 PM
Characterization of n-type Bismuth Telluride Processed via Selective Laser Melting: Ryan Welch1; Haidong Zhang1; Saniya LeBlanc1; 1George Washington University
Thermoelectric modules are solid-state energy conversion devices that are used in thermal management and waste heat recovery applications. Additive manufacturing of thermoelectric materials may offer advantages through influencing material transport properties: Seebeck coefficient, thermal conductivity, and electrical conductivity. This work investigates selective laser melting of n-type bismuth telluride (Bi2Se0.3Te2.7). We manufactured ingots of bismuth telluride and analyzed the meso-, micro- and nanostructure via optical and electron microscopy. Scanning electron and optical microscopy results showed the laser melted samples had a high porosity and non-equiaxed grain structure. Energy dispersive spectroscopy line scans revealed varying concentrations of constituent elements. Transmission electron microscopy confirmed the existence of nanoscale bismuth oxide inclusions within the sample. We concluded that the shift in primary charge carriers from electrons to holes was due to oxide formations throughout the material.
2:20 PM
Strand Casting and Thermal Properties of Submillimeter Metallic Glass Wires: Ayodele Olofinjana1; James Kern2; 1University of the Sunshine Coast; 2The Welding Institute
Engineeringly, small-sized wire-shaped products present the best combinations of mechanical properties but the path for manufacturing sub-millimeter wire often consists of many processes. The idea of the direct casting of wire, therefore, remains attractive because of the potential to eliminate intermediate processes that in principle can lead to cost and energy savings. Reported cases of wire casting are fraught with imprecise process parameters, inconsistent products, and a small scale. In this work, we report the parameters for a three-strand casting process that produced Fe-based amorphous structured wires. The castings were conducted in laser-drilled crucibles. The effects of melt superheat, nozzle design, orifice spacing, wire formation, and thermal properties were studied. It is shown that melt superheat of less than 100K and orifice spacing of more than 1mm are required to produce smooth and amorphous structured wires. The thermal stabilities were composition-dependent and mechanical properties ranged from 3000 – 4000MPa.
2:40 PM
Defect Recognition on Coating Layer Using PinPoint Nanomechanical Mode in Atomic Force Microscopy: Gil Min1; Gabriela Mendoza1; Cathy Lee1; Moses Lee1; Jake Kim1; Keibock Lee1; 1Park Systems
Surface coating techniques is widely used industrially to prevent surface abrasion and corrosion. Atomic Force Microscopy (AFM)is largely used in material surface research allowing reviewing and inspection quality control for possible defects. The aim was to demonstrate AFM PinPoint for analyzing generated defects during coating process. The first test involved a scratch produced over the surface of a coated glass substrate. The second test featured a scratched glass substrate whose surface was subsequently re-coated. Topography, adhesion energy and modulus images from two samples with defects created before and after coating were obtained. Examining adhesion and modulus images of the scratch before coating, they show no visible difference in mechanical properties.Where the glass substrate is scratched after the coating, a clear contrast is shown. AFM can be used for diverse applications in the coating industry because of its ability to examine the surface properties otherwise not observable by studying topography alone.