Materials Science and Engineering Commons^™

Effect On Mechanical Properties Of Aluminium Alloy Composites On Adding Ash As Reinforcement Material, Mohd Zafaruddin Khan, Mohd Anas, Ather Hussain, Md Irshadul Haque, Kamran Rasheed

Journal of Metals, Materials and Minerals

To produce Al-matrix cast particle composites, wettability of the ceramic particles by liquid Al is essential. To improve wettability of the solution, few elements such as Mg and Si are added into Al melt to incorporate the ceramic particles. The present investigation has been focussed on the utilization of abundant available industrial waste such as fly ash and bagasse ash in useful manner by dispersing it into Eutectic Al-Si alloy LM6 Containing 10.58% Si to produce composites by liquid casting route. The mechanical properties such as Brinell Hardness and Ultimate tensile strength has been investigated. The test results of the …

Effect Of Temperature Dropping During Solution Treatment In Rejuvenation Heat Treatment On Final Microstructures Of Udimet 520, Kritsayanee Saelor, Panyawat Wangyao

Journal of Metals, Materials and Minerals

Udimet 520 is a low precipitation hardened nickel-based superalloy, which is made to be turbine blades at high temperature. After long-term service, the microstructure of the turbine blades could be degraded, then the mechanical properties are worse than the new ones. The rejuvenation heat treatment of degraded turbine blades, which are made of cast Udimet 520, is following by solution treatment at 1,121C / 4 hours and then double aging processes, which include primary aging at 843 C / 24 hours and secondary aging at 760 C / 16 hours, respectively.However, in practical reheat treatment processes, the temperature during solution …

Effect Of Tig Welding Parameters On Strain-Age Cracking In Joining Nickel-Based Superalloy, Gtd-111 With Inconel 625, Athittaya Athiroj, Panyawat Wangyao

Journal of Metals, Materials and Minerals

Excellent mechanical properties at high temperature of nickel-based superalloys brought them to extensive application in severe operating conditions. However, the great mechanical properties deteriorate after long-term exposure to high temperature and it frequently causes failure of the component e.g. cracking. TIG welding is considered as an economical way to refurbish the minor damage component as replacement with new one is costly due to high material cost and complexity in manufacturing processes. Unfortunately, heat from welding that applies to the component may create new cracks during and after process from liquation and strain-age cracking. This phenomena is problem especially in precipitation-hardened …

Processing Of Nano Fillers In Nitrile Rubber A Novel Technique, Abitha V. K., Ajay Vasudeo Rane, K. Rajkumar

Journal of Metals, Materials and Minerals

Dispersion of various nano fillers like Nano silica, nano clay, Nano TiO2, etc has been attempted in NBR rubbers using new technique of dispersion. Liquid NBR is taken as dispersion media for nano fillers in polymer matrix and polymer nano composites were characterized by Rubber Process Analyzer [RPA-2000, USA]. The dispersion of the nano fillers were investigated by XRD, SEM-EDS. The effect of increasing nano- fillers on mechanical properties like tensile strength, modulus and Elongation at break was studied. Hot air ageing of polymer nano composites was also studied.Dispersion of various nano fillers like Nano silica, nano clay, Nano TiO2, …

Microstructure Based Finite Element Simulation Of Jco Forming Process For Pipeline X65, Wut Thianngoen, Saranya Kingklang, Vitoon Uthaisangsuk

Journal of Metals, Materials and Minerals

In recent years, strong increases in energy demand have become the most important issue in every section. High strength pipeline steels make large contribution to cost reduction for fuel transportation in oil and gas industries due to their great combination of optimal strength and toughness properties. Mechanical properties of pipeline steel tubes are significantly influenced by their microstructure characteristics, which in turn are controlled by the production. In this work, the JCO forming process of gas pipeline tube made of hotrolled steel grade X65 with ferrite/pearlite microstructure was investigated by means of a FE multiscale modeling approach. Three different scales …

Experimental Investigation And Thermal Modeling On Electro Discharge Drilling Of Pcd, Farnaz Nourbakhsh

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

This study presents an experimental investigation and finite element simulation of Electro Discharge Drilling (ED-Drilling) of Polycrystalline Diamond (PCD). PCD has many outstanding properties including uniformly high hardness, high wear resistance and strong corrosion which are the main causes of widely using PCD. While PCD has many advantages and an important role in industrial applications, its high level of hardness and wear resistance cause this material to be difficult to form and machine by using traditional machining methods. EDM as a nontraditional machining process is an effective method among other non-traditional methods for PCDs due to its low cost and …

Effects Of Expected Service Life Exposures On The Functional Properties And Impact Performance Of An American Football Helmet Outer Shell Material, David E. Krzeminski

Dissertations

The purpose of this dissertation is to gain a greater scientific understanding of the changes in functional material properties and impact performance of an American football helmet outer shell material under expected service life exposures. The research goals are to (i) quantify chemical, physical, thermal, and mechanical degradation of an American football outer shell material under expected environmental conditions and (ii) develop a linear drop test impact protocol to employ expected on-field impact conditions to American football helmet components and a plaque-foam (i.e., shell-liner) surrogate. Overall, a step-wise progression of analysis was demonstrated to concurrently quantify and understand changes in …

Molecular Dynamics Simulation Of Force-Controlled Nanoindentation, Keaton Jaramillo

Mechanical Engineering Undergraduate Honors Theses

The aim of this honors research is to develop a force-controlled nanoindentation algorithm for molecular dynamics simulation. The algorithm was tested on Silicon using the Tersoff potential and Gold using the Embedded-Atom Method (EAM) potential. The effect of varying the damping parameters that adjust the system pressure and changing run length between force iterations is explored. The force-controlled algorithm was developed and shown to be working by correlating pop-in events shown in the force versus displacement (P-h) curves to visualization software showing phase transformation or dislocation events in the sample.

Mechanical Reliability Of Porous Low-K Dielectrics For Advanced Interconnect: Study Of The Instability Mechanisms In Porous Low-K Dielectrics And Their Mediation Through Inert Plasma Induced Re-Polymerization Of The Backbone Structure, Yoonki Sa

Material Science and Engineering Dissertations - Archive

Continuous scaling down of critical dimensions in interconnect structures requires the use of ultralow dielectric constant (k) films as interlayer dielectrics to reduce resistance-capacitance delays. Porous carbon-doped silicon oxide (p-SiCOH) dielectrics have been the leading approach to produce these ultralow-k materials. However, embedding of porosity into dielectric layer necessarily decreases the mechanical reliability and increases its susceptibility to adsorption of potentially deleterious chemical species during device fabrication process. Among those, exposure of porous-SiCOH low-k (PLK) dielectrics to oxidizing plasma environment causes the increase in dielectric constant and their vulnerability to mechanical instability of PLKs due to the loss of methyl …

Mechanical Properties Of Interpenetrating Phase Composites Using Open-Cell Al Foams With Natural Rubber And Polyethylene, Kunmutta Angamnuaysiri, Seksak Asavavisithchai

Journal of Metals, Materials and Minerals

Interpenetrating phase composites (IPCs) were produced by conventional casting process, in vacuum atmosphere, using open-cell Al foams as matrix, and filled with either natural rubber or polyethylene. Mechanical properties of IPCs strongly depends on types of polymeric phases. It is found that the IPCs with polyethylene show an increase in compressive strength as well as failure strain. However, a large decrease of compressive strength is observed in the IPCs with natural rubber, as a result of cracks along the interface between Al foam and the rubber. These cracks are distributed throughout foam structure in the IPCs.

Microstructure And X-Ray Diffraction Analysis Of Al-Cu Couples Diffused At High Temperature, Jaime Hinojosa-Torres, Juan Manuelaceves-Hernández, Andres Herrera-Vázquez, Victor Manuelcastaño-Meneses

Journal of Metals, Materials and Minerals

By employing a thermal field of 813 K, couples of Al with Cu were welded as consequence of the atomic diffusion. The periods of permanency inside the field were 200, 320 and 480 hours. After the periods of test, SEM observations show the formation of two contiguous plate likes (~15 to 30 micrometres, width) that they are in normal position to the concentration gradient. By utilizing elemental analyses and X-ray diffraction techniques one plate like was identified as the h2 phase (CuAl) and the other one as the q phase (CuAl2) of the aluminium-copper system. Immediate to the q plate …

A Platform For Fast Detection Of Let-7 Micro Rna Using Polyaniline Fluorescence And Image Analysis Techniques, Partha P. Sengupta

Master's Theses

The project describes a new strategy for transducing hybridization events through modulating intrinsic properties of the electroconductive polymer polyaniline (PANI). When DNA based probes electrostatically interact with PANI, its fluorescence properties are increased, a phenomenon that can be enhanced by UV irradiation. Hybridization of target nucleic acids results in dissociation of probes causing PANI fluorescence to return to basal levels. By monitoring restoration of base PANI fluorescence as little as 10^-11 M (10 pM) of target oligonucleotides could be detected within 15 minutes of hybridization. Detection of complementary oligos was specific, with introduction of a single mismatch failing to …

Hybrid Aryl-Ether-Ketone And Hyperbranched Epoxy Networks, John Misasi

Dissertations

In this dissertation, relationships between chemical structures, cure kinetics and network architectures are correlated to bulk mechanical properties for novel, hybrid epoxy-amine networks. The work is split into two primary sections: the first is the synthesis and characterization of multifunctional glassy networks based on aryl-ether-ketone diamine curatives, while the second is based on the synthesis and characterization of hyperbranched epoxy polymers and their resulting networks.

Three aryl-ether-ketone (AEK) diamines of increasing molecular weights were synthesized and used to cure 4,4’-tetraglycidylether of diaminodiphenylmethane (TGDDM); the resulting networks were compared to 4,4’-diaminodiphenyl sulfone cured TGDDM. Architectural differences were created by varying cure …

Polyacrylonitrile Copolymers: Effects Of Molecular Weight, Polydispersity, Composition, And Sequencing On Thermal Ring-Closing Stabilization, Jeremy D. Moskowitz

Dissertations

Controlled polyacrylonitrile (PAN)-based carbon fiber precursors with defined molecular weights, polydispersities, compositions, and architectures have been prepared for their study on thermal ring-closing stabilization behavior. PAN and its copolymers of number average molecular weights exceeding 170,000 g/mol were successfully synthesized via low temperature reversible addition-fragmentation chain transfer (RAFT) polymerization. RAFT polymerizations of PAN-based precursors were compared to conventional free radical solution polymerizations with a focus on the effects of molecular weight and polydispersity on structural evolution and cyclization efficiency. When RAFT polymerization was extended to copolymers, it was found that RAFT copolymers achieved greater cyclization intensities and improved thermal stability …

Development Of Dual-Cure Hybrid Polybenzoxazine Thermosets, Jananee Narayanan Sivakami

Dissertations

Polybenzoxazines are potential high performance thermoset replacements for traditional phenolic resins that can undergo an autocatalytic, thermally initiated ring - opening polymerization, and possess superior processing advantages including excellent shelf-life stability, zero volatile loss and limited volumetric shrinkage. The simplistic monomer synthesis and availability of a wide variety of inexpensive starting materials allows enormous molecular design flexibility for accessing a wide range of tailorable material properties for targeted applications. Despite the fact, once fully cured, benzoxazines are difficult to handle due to their inherent brittleness, leaving a very little scope for any modifications. The motivation of this dissertation is directed …

Designing Optical Properties In Infrared Glass, Benn Gleason

All Dissertations

Chalcogenide glasses (ChGs) are well-known for their attractive optical properties, such as high refractive index and transparency in across infrared wavelengths. ChGs also possess the ability to compositionally tune properties such as the refractive index, the thermo-optic coefficient, and other non-optical properties. Chalcogenide glasses with compositionally tailored physical and optical properties will provide optical designers with new materials necessary to create novel infrared imaging systems requiring new or expanded functionality. This dissertation has evaluated the relationship between glass composition, the resulting atomic structure, and resulting optical and thermo-optical properties, with specific focus on the infrared refractive index and the thermo-optic …

Synthesis And Characterization Of Oleophobic Fluorinated Polyester Films, Tugba Demir

All Dissertations

The study presented in this dissertation is dedicated to the synthesis and characterization of oleophobic fluorinated polyester films. Specifically, the blending of oleophilic polyethylene terephthalate (PET) with low surface energy materials such as fluorinated polyesters has been used in order to fabricate oleophobic PET films. First, fluorinated polyesters (P(PF-oate-R)) possessing different end-groups (-COOH, -OH and -CF3) are synthesized via polycondensation reaction of isophthaloyl chloride with perfluoro ether alcohols. Then, they are solvent-blended with PET at various concentrations to obtain oleophobic polyester films of different compositions. In addition, the films are annealed to investigate the effect of annealing on surface properties …

Construction Of An Initiated Chemical Vapor Deposition (Icvd) Reactor And Deposition Of Polytetrafluoroethylene (Ptfe) Thin Films Using Perfluoro-1-Octanesulfonyl Fluoride As The Initiator, Edgar Kiprop Kosgey

Graduate Theses/Dissertations

Initiated Chemical Vapor Deposition (iCVD) is a surface polymerization technique that is different from other traditional chemical vapor deposition (CVD) techniques. iCVD is carried under a vacuum without the use of solvents, therefore eliminating contaminations. An initiator and a monomer are metered into a vacuum reactor chamber. Inside the reaction chamber is an array of resistively heated filaments and a cooled substrate stage. Monomer species adsorb on to the cooled substrate surface underneath the filament array. The thermal energy from the resistively heated filaments breaks the bonds in the initiator molecule, generating free radicals. These generated free radicals chemisorb to …

Effect Of Ni On The Formability And Texture Of Hot Rolled Weathering Steel, Gadadhar Sahoo, I. S. Wani, S. B. Kumar, Balbir Singh, Atul Saxena, R. Basu

Journal of Metals, Materials and Minerals

Formability behavior in two grades of hot rolled low carbon weathering steel with varying nickel content i.e., SCR 1 (Fe-0.116P-0.018Ni) and SCR 2 (Fe-0.115P-0.34Ni), have been evaluated in relationship to microstructure, EBSD estimated orientation distribution function (ODF), special boundary nature, mechanical properties and formability parameters like tensile stain hardening exponent (n) and plastic anisotropy ratio (r). The alloy sample SCR 1 exhibited improved formability characteristics in terms of stain hardening exponent (n) and plastic anisotropy ratio (r). This was mainly attributed to relatively higher fraction of the ND//<111> orientation or the ? fibre texture component and increased presence of sigma …

An Approach To Model Plastic Deformation Of Metallic Plates In Hypervelocity Impact Experiments, Shawoon Kumar Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Space structures are subjected to micro-meteorite impact at extremely high velocities of several kilometers per second. Similarly, design of military equipment requires understanding of material behavior under extremely high pressure and temperature. Study of material behavior under hypervelocity impact (HVI) poses many challenges since few researchers so far have approached this problem. Material models, equations of the state, and fracture mechanics are not well understood under these conditions.

The objective of this research is to present an approach for studying plastic deformation of metallic plates under HVI conditions. A two-stage light gas gun can be used to simulate these conditions …