Other Materials Science and Engineering Commons^™

Effect Of Niobium Addition On Corrosion Behavior, Mechanical Properties, And Microstructures Of U6zr Alloys In An Aerated Environment, Masrukan Masrukan, Djati Handoko, Dede Djuhana, Rohmad Sigit, M. Husna Al Hasa, Wisnu Ari Adi, Siti Mardiah

Makara Journal of Science

The effect of Nb addition on the corrosion behavior of U–6Zr alloys within an aerated, demineralized water (DW) environment (pH 5.61) and its correlation of this addition with the mechanical and microstructural properties of the alloys were investigated. The U–6Zr–xNb alloys (x = 1, 4, and 7 wt.%) were synthesized by arc-melting U, Zr, and Nb. Additionally, the samples were mounted and polished, after which they were subjected to electrochemical corrosion analysis using a potentiostat. This evaluation was conducted in a DW medium (pH 5.6), representing an aerated atmosphere, at room temperature (27°C) and a potentiodynamic scan rate of 1 …

Magnetically Impelled Arc Butt Welding And Straight Tube Butt Welding Analysis Of Boiler Grade Tube Joints, Santhosh Kumar S

Theses and Dissertations

Boiler-graded tubes of T11, T12, T91, and T92 materials with a thickness of 4.5 mm thick and 44.5 mm outer diameter were selected for the Straight Tube Butt Welding process using Hot Wire (STBW-HW) and Cold Wire (STBW-CW) conditions. Moreover, the research investigates and compares the welding characteristics of dissimilar T11 and T91 boiler-graded tubes using STBW - HW & Magnetically Impelled Arc Butt (MIAB) welding techniques. Similar and dissimilar welding was performed in STBW – HW & CW conditions.

In dissimilar welding, the tensile strength was higher in the T11-T91 STBWHW joints of 663 MPa than in the T12-T92 …

Understanding Firn Dynamics: Modeling And Microstructure From East Antarctica, Ilyse Horlings

Dartmouth College Ph.D Dissertations

Glacier ice is formed from the accumulation of snow and its compaction through a transitional material called firn. Firn dynamics are fundamentally influenced by climatic factors, such as temperature and snow accumulation rate, and so are crucial for understanding a number of cryospheric applications. For example, ice-sheet mass loss contributions to sea-level rise from repeat satellite-altimetry observations depend on calculating firn density and its evolution. Past atmospheric gases in ice core bubbles are often younger than the surrounding ice, and their exact age depends on how firn closes off interconnected pores to become impermeable. Models often estimate bulk properties, such …

Deep-Learning Based Microstructure Reconstruction And Generation, Cameron J. Maloney, Lucas Taliaferro

College of Engineering Summer Undergraduate Research Program

Characterizing the microstructural behavior of materials is crucial for understanding their properties and performance. Traditional imaging methods, such as optical microscopy and electron microscopy, are effective but costly and time-consuming. Computational approaches can reduce costs and time while expanding the accessibility of microstructural analysis through the generation of new microstructure images. Traditional computational approaches, namely descriptor-based approaches, are slow but effective in low-data scenarios. Modern approaches use machine learning (ML), which is faster but often requires a lot of data to approach the performance of descriptor-based methods. This research leverages a special data-efficient Generative Adversarial Network (GAN) architecture to artificially …

Processing, Stability, And High-Temperature Properties Of Doped Lacro3-Based Refractory Ceramics And Composites For Harsh Environments Sensing Applications, Javier A. Mena

Graduate Theses, Dissertations, and Problem Reports (ETD)

In order to test and monitor the operational stability and conditions of various energy, transportation, and manufacturing systems and their components, accurate sensors capable of operating at temperatures over 1000 °C in various environments for long durations are required. In addition, many of these harsh environmental systems do not permit sensors to be directly inserted into the environment, so the sensors need to be embedded into the surrounding support or thermal protective materials. Some technological and industrial applications that require the use of harsh environment conditions sensing include nuclear and chemical reactors, jet engines, heavyduty gas turbines, rotating bearings in …

Optimization Of Porosity In Cold Spray Produced Copper And Zinc Coatings, Cameron Hughes

Graduate Theses & Non-Theses

Since its invention in 1981, the cold spray (CS) additive manufacturing (AM) process has been studied and optimized to produce well-adhered, dense material coatings. CS can operate at a wide range of temperatures if the feed material remains in a solid state. Copper and zinc were studied to characterize and understand the effects of heating element voltage, travel speed, and standoff distance on deposit porosity, grain size, microhardness, and coating thickness. Samples were sprayed on 3.2 mm x 25 mm x 150 mm 6061 aluminum substrates. Sections were taken from the middle of the samples to represent steady-state conditions. Sample …

Hydcem: A New Cement Hydration Model, Niall Holmes, Denis Kelliher, Mark Tyrer

Conference papers

Hydration models are useful to predict, understand and describe the behaviour of different cementitious-based systems. They are indispensable for undertaking long-term performance and service life predictions for existing and new products for generating quantitative data in the move towards more sustainable cements while optimising natural resources. One such application is the development of cement-based thermoelectric applications.

HYDCEM is a new model to predict the phase assemblage, degree of hydration, heat release and changes in pore solution chemistry over time for cements undergoing hydration for any w/c ratio and curing temperatures up to 450C. HYDCEM, written in MATLAB, is aimed at …

A Study On Ultrasonic Energy Assisted Metal Processing : Its Correeltion With Microstructure And Properties, And Its Application To Additive Manufacturing., Anagh Deshpande

Electronic Theses and Dissertations

Additive manufacturing or 3d printing is the process of constructing a 3-dimensional object layer-by-layer. This additive approach to manufacturing has enabled fabrication of complex components directly from a computer model (or a CAD model). The process has now matured from its earlier version of being a rapid prototyping tool to a technology that can fabricate service-ready components. Development of low-cost polymer additive manufacturing printers enabled by open source Fused Deposition Modeling (FDM) printers and printers of other technologies like SLA and binder jetting has made polymer additive manufacturing accessible and affordable. But the metal additive manufacturing technologies are still expensive …

Deformation Correlations And Machine Learning: Microstructural Inference And Crystal Plasticity Predictions, Michail Tzimas

Graduate Theses, Dissertations, and Problem Reports (ETD)

The present thesis makes a connection between spatially resolved strain correlations and material processing history. Such correlations can be used to infer and classify prior deformation history of a sample at various strain levels with the use of Machine Learning approaches. A simple and concrete example of uniaxially compressed crystalline thin films of various sizes, generated by two-dimensional discrete dislocation plasticity simulations is examined. At the nanoscale, thin films exhibit yield-strength size effects with noisy mechanical responses which create an interesting challenge for the application of Machine Learning techniques. Moreover, this thesis demonstrates the prediction of the average mechanical responses …

Effect Of Er On Microstructure And Electrochemical Performance Of Al–Zn–In Anode, Zhengbing Xu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Effect Of Heat Input On Microstructure And Formability Of Dp980 Steel Welded Joints By Fiber Laser Welding, Qian Sun

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Ferromagnetic Shape Memory Alloy Microwires, Xuexi Zhang, Mingfang Qian, Hehe Zhang, Lin Geng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Finite Element Simulation And Experimental Study Of The Effect Of Combining Ultrasonic Vibration With Ecap Process On Pure Aluminum 1050, Saeed Bagherzadeh, Yanfei Liu, Karen Abrinia, Qingyou Han

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Synthesis, Structure, Properties And Applications Of Nanoporous Silicon And Palladium, Xu Jiang

Theses and Dissertations--Chemical and Materials Engineering

Nanoporous (np) materials with pore size below 100 nano-meters exist naturally in biological and mineral structures, and synthetic np materials have been used industrially for centuries. Np materials have attracted significant research interest in recent decades, as the development of new characterization techniques and nanotechnology allow the observation and design of np materials at a new level. This study focuses on two np materials: nanoporous silicon (np-Si) and nanoporous palladium (np-Pd).

Silicon (Si), because of its high capacity to store lithium (Li), is increasingly becoming an attractive candidate as anode material for Li ion batteries (LIB). One significant problem with …

Structural, Magnetic And Microstructural Studies Of Composition-Modified Sm–Co Ribbons, Xiujuan Jiang

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

There is an increasing interest in developing desirable microstructures in hard magnetic materials. Sm-Co-based magnets, bearing superior intrinsic magnetic properties, are good candidates for further development. Two Sm-Co-based alloys, (Sm₁₂Co₈₈)_100-x-yCr_yC_x (taking SmCo₇ phase) and SmCo_4-xFe_xB (a derivative of SmCo₅ phase), were produced using melt-spinning technique. The magnetic properties are correlated to the structural and microstructural properties.

Within the SmCo₇ stoichiometry, cumulative effects of Cr and C additions on the structural and magnetic properties have been investigated. Experimental results have shown that these additions along …

Microstructure And Work Function Of Dispenser Cathode Coatings: Effects On Thermionic Emission, Phillip D. Swartzentruber

Theses and Dissertations--Chemical and Materials Engineering

Dispenser cathodes emit electrons through thermionic emission and are a critical component of space-based and telecommunication devices. The emission of electrons is enhanced when coated with a refractory metal such as osmium (Os), osmium-ruthenium (Os-Ru), or iridium (Ir). In this work the microstructure, thermionic emission, and work function of thin film Os-Ru coatings were studied in order to relate microstructural properties and thermionic emission.

Os-Ru thin film coatings were prepared through magnetron sputtering and substrate biasing to produce films with an array of preferred orientations, or texture. The effect of texture on thermionic emission was studied in detail through closely-spaced …