22 research outputs found
Understanding the mechanical properties of nanotwinned copper using molecular dynamics simulation
No full textDesign and Development of an Interdisciplinary Nanotechnology Courses for STEM Education
No full textTitle: Design and Development of an Interdisciplinary Nanotechnology Courses for STEM Education
Mujibur Rahman Khan1*, Ishraq Shabib2, Rafael Quirino3, Aniruddha Mitra4
1,4Assistant Professor; Department of Mechanical Engineering, Georgia Southern University
2 Department of Engineering; Central Michigan University
3 Department of Chemistry; Georgia Southern University
The purpose of this project is to design and introduce interdisciplinary nanotechnology courses for STEM education. The planned courses are: a first year experience course and an applied studio laboratory course. Inclusion of a first-year-experience (FYE) module (title: Introduction to Nanoscale Science and Engineering) will expose freshmen to nanotechnology, serving as a recruitment tool for the more advanced senior-level courses. The courses will be cross-listed in other colleges for additional cross-talk between disciplines and is meant to develop interest and excitement about nanotechnology. The 2nd course (Title: Nanomaterials and Nonmanufacturing) will be a four hours studio (lecture and Lab) course. Lecture modules e will be divided into four modules where fundamental knowledge on nanoscale matter and nanotechnology will be taught, integrating engineering, chemical, physical, biological, manufacturing, environmental health, and economic aspects. The integrated laboratory section is designed to provide students with hands-on experience with fabrication and testing of a nanoscale materials, devices and characterization tools. The lab will also incorporate simulation and modeling at nanoscale to engage students in design of nanomaterials and devices. Empirically defensible educational techniques will be used to deliver an innovative, interdisciplinary curriculum. The lecture and studio course teach not just engineering, but chemistry, biology, physics, environmental science, and economics, each delivered by experts in the various fields. The intellectual merit of this project is that it will provide an important initial model for how to approach interdisciplinary nanotechnology education at the post-secondary level. The newly designed courses and laboratory modules will implement the best practices in education to integrate nanotechnology into the existing curriculum. The course modules incorporate real world experiences and future vision to excite and enrich first-year experience and enhance engagement opportunities for upper level students. The project is designed to produce intellectual fusion across the academic spectrum allowing students to engage outside of the traditional silos of education.
Key words: Nanotechnology, Interdisciplinary, STEM, Nanomaterla
Effect of Heating Rate on Microstructure and Corrosion Resistance of Quenched and Tempered 8620 Low Carbon Alloy Steel
No full textIn the process of heat treatment of 8620 low alloy steel, the heating rate is a critical parameter that must be carefully controlled to achieve the desired combination of microstructural features, mechanical properties, and corrosion resistance while simultaneously ensuring process efficiency and cost-effectiveness. This study investigates, for the first time, the microstructural evolution and electrochemical properties of 8620 steel under identical quenching and tempering heat treatment routes with slow-rate (SR) and fast-rate (FR) heating rates. Microstructural analysis revealed martensitic phases for SR, while FR exhibited a dual-phase microstructure containing ferrite. Upon tempering, for both samples, the martensite transformed into tempered martensite, with tempered (Temp) FR exhibiting around 50% smaller ferrite grains. Mechanical testing indicated that SR had 17% higher hardness than FR, although hardness decreased after tempering by 22% (SR) and 17% (FR). All electrochemical tests indicated that the as-quenched SR exhibited significantly superior corrosion resistance than FR. For instance, the polarization resistance of SR was 440 Ω higher than that of the FR samples. Tempering resulted in a considerable decrease in corrosion resistance for Temp SR, whereas Temp FR improved. Electrochemical characterization revealed Temp FR displayed close-to-ideal capacitive behavior and low double-layer capacitance, indicating enhanced overall corrosion resistance
Effects of Grain Boundary Density and Temperature on Thermal Conductivity of Fe-10%Cr Alloys with [001] Tilt Boundaries: An Atomistic Study
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Effect of dissolution of magnesium alloy AZ31 on the rheological properties of Phosphate Buffer Saline
No full textEnhanced Corrosion Resistance of TiZrN-Coated Additively Manufactured 8620 Low-Alloy Steel in Nitrate Salt Solution and Salt Bath
No full textIn this study, corrosion resistance of TiZrN-coated additively manufactured (3D-printed) 8620 steel has been separately studied in a 60–40 wt% NaNO3 + KNO3 molten salt and in an aqueous nitrate salt environment. Microstructural characterization of the as-built bare 3D-printed 8620 sample revealed martensitic microstructures. High-temperature corrosion analysis in molten nitrate salt revealed improved film stability and corrosion resistance of the coating. The coated 3D-printed sample showed no scale of corrosion products, whereas the bare 3D-printed sample exhibited a layer of corrosion products of 2.62 ± 0.24 µm thickness. Potentiodynamic polarization and electrochemical impedance spectroscopy tests in aqueous nitrate salts at room temperature exhibited an ~8-fold decrease in corrosion current density and a ~7-fold increase in charge transfer resistance, indicating enhanced corrosion resistance of the coated 8620. The coated wrought 8620 showed comparable corrosion resistance to that of the coated 3D-printed sample. However, in aqueous solution, the bare 3D-printed sample exhibited localized corrosion, whereas the bare wrought revealed uniform corrosion on the surface
Distinctive Features and Fabrication Routes of Metallic-Glass Systems Designed for Different Engineering Applications: A Review
No full textMaterials with a disordered atomic structure, often termed glassy materials, are the focus of extensive research due to the possibility of achieving remarkable mechanical, electrochemical, and magnetic properties compared to crystalline materials. The glassy materials are observed to have an improved elastic modulus combined with a higher strength and hardness. Moreover, better corrosion resistance in different mediums is also observed for glassy solids, which is difficult to attain using conventional crystalline materials. As a result, the potential applications of metallic-glass systems are continually increasing. Amorphous materials are usually divided into two categories based upon their size. Materials with a thickness and diameter larger than the millimeter (mm) scale are termed as bulk metallic glass (BMG). However, the brittle nature of the bulk-sized samples restricts the size of metallic-glass systems to the micron (µm) or nanometer (nm) range. Metallic glasses with a specimen size in the scale of either µm or nm are defined as thin-film metallic glass (TFMG). In this review, BMGs and TFMGs are termed as metallic glass or MG. A large number of multi-component MGs and their compositional libraries reported by different research groups are summarized in this review. The formation of a multicomponent metallic glass depends on the constituent elements and the fabrication methods. To date, different unique fabrication routes have been adopted to fabricate BMG and TFMGs systems. An overview of the formation principles and fabrication methods as well as advantages and limitations of conventional MG fabrication techniques is also presented. Furthermore, an in-depth analysis of MG inherent properties, such as glass forming ability, and structural, mechanical, thermal, magnetic, and electrochemical properties, and a survey of their potential applications are also described
