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Full-Text Articles in Engineering

An Investigation Of Incipient Melting During Solution Heat Treatment Of 7050 Aluminum Forgings And Its Effect On Corrosion Properties, Thomas Kilkenny Jun 2015

An Investigation Of Incipient Melting During Solution Heat Treatment Of 7050 Aluminum Forgings And Its Effect On Corrosion Properties, Thomas Kilkenny

Materials Engineering

7050 alloy (6.2Zn-2.3Mg-2.3Cu-0.12Zr) is a structural aluminum alloy commonly used in the aerospace industry. Its rich chemistry makes it susceptible to incipient melting. Incipient melting is a phenomenon where areas with high local alloy content melt before the rest of the material. This can cause a degradation of mechanical and corrosion properties. A six by four factor solution heat treatment trial was conducted. Six solution heat treatment temperatures, 890- 940°F in 10°F increments, and four times, 1, 2, 4, and 6 hours, were used. Incipient melting was observed in the 910°F, 6 hour solution heat treatment and all 920-940°F solution …


Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley Jun 2015

Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley

Materials Engineering

Atom level computer simulations of the arabinan and cellulose interface were performed to better understand the mechanisms that give arabinan-cellulose composites (ArCCs) their strength with the goal to improve man-made ArCCs. The molecular dynamics (MD) software LAMMPS was used in conjunction with the ReaxFF/c force field to model the bond between cellulose and arabinan. A cellulose nanocrystal with dimensions 51 x 32 x 8 Å was minimized with various weight percent of water, 0%, 3%, 5%, 8%, 10%, and 12%. After the system was equilibrated for at least 100,000 femtoseconds, an arabinan molecule composed of 8 arabinose rings was added …


Effect Of Heat Treatment On The Mechanical Properties In Natural Bamboo, Austin Levy, Mackenzie Kirkpatrick Jun 2015

Effect Of Heat Treatment On The Mechanical Properties In Natural Bamboo, Austin Levy, Mackenzie Kirkpatrick

Materials Engineering

Previous studies have shown that heat treatments have the ability to improve mechanical strength and stiffness in hardwood species. Compared to structural hardwoods, bamboo is a more sustainable and globally viable renewable resource. Therefore, Bambusoides vivax (timber bamboo) culms were fabricated into flat, rectangular cross-section samples with varying cellulose content to be heat treated and tested for mechanical properties. All samples were heat treated (HT) twice. The first HT was a normalization of all samples at 103 +/- 3 °C. The second HT was performed at various times and temperatures ranging from 130°C to 170°C for 0.5 to 3 hours. …


Elevated Temperature Effects On The Mechanical Properties Of Age Hardened 6xxx Series Aluminum Alloy Extrusions, Rachael Donovan, Rose Fortune, Robert Trout Jun 2015

Elevated Temperature Effects On The Mechanical Properties Of Age Hardened 6xxx Series Aluminum Alloy Extrusions, Rachael Donovan, Rose Fortune, Robert Trout

Materials Engineering

The purpose of this project is to determine if over-aging of aluminum causes the yield or tensile strength to fall below the minimum strength values set by the aluminum industry. Extruded aluminum alloys, 6061-T6, 6063-T6, and two proprietary alloys, HS6X-T6 and RX82-T6, were exposed to reheating treatments at extended times and temperatures. The three temperatures were 350°F, 390°F, and 425°F. The times of reheat increased logarithmically from 30 minutes to 64 hours. The samples were tensile tested to determine the tensile strength and yield strength. Statistical methods helped model the behavior of yield and tensile strength as a function of …


Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair Jun 2015

Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair

Materials Engineering

Raytheon Company currently uses a Forest Products Laboratory (FPL) paste etchant for preparing aluminum surfaces for adhesive bonding, and FPL is a source of hazardous hexavalent chromium. The goal of this study was to evaluate a less-toxic P2 paste etchant as a possible replacement. Coupons of 2024-T3, 6061-T6, and 7075-T6 grades of aluminum alloy were solvent-degreased, abrasively cleaned, and etched at room temperature using P2 paste following a strict protocol adopted from Raytheon. Coupons were then left exposed to air for assigned time intervals (or “outlife” times) of 0, 1, 4, 8, 16, and 63 or 72 hours. The aluminum …


Effects Of Initial Forging Temperature, Cooling Rates, And Carbon Content On Primary Alpha Formation In Ti-6al-4v, James Tillman, Hui Wei Jun 2015

Effects Of Initial Forging Temperature, Cooling Rates, And Carbon Content On Primary Alpha Formation In Ti-6al-4v, James Tillman, Hui Wei

Materials Engineering

Ti-6Al-4V is an alpha-beta titanium alloy system, which contains both alpha and beta phases at room temperature. Both alpha and beta phases provide Ti-6Al-4V a range of different properties for a range of applications. In order to improve the energy efficiency and better satisfy customers’ requirements of less than 52% primary alpha phase, Weber Metals sponsored this project to study the effects of carbon content, forging temperature, and cooling rates on primary alpha formation in Ti-6Al-4V alloys. There has been a lot of discussion as to whether or not carbon, a known alpha stabilizer, will affect the microstructure in small …


Effects Of Composition And Solid Solution Strengthening On The Compression Strength Of Iron-Based Hardfacing Alloys, Tyler Wiggins, Samuel Garrison-Terry Jun 2015

Effects Of Composition And Solid Solution Strengthening On The Compression Strength Of Iron-Based Hardfacing Alloys, Tyler Wiggins, Samuel Garrison-Terry

Materials Engineering

Three iron-based hardfacing alloys were fabricated to have a tungsten strengthened matrix with varying compositions of 10-15, 20, and 30 wt% tungsten/chrome boride content. The fourth sample was fabricated to have a molybdenum solid solution strengthened matrix with 10-15 wt% W/Cr Boride content. This project focuses on the compressive strength of iron-based hardfacing alloys. Preliminary compression tests with Scoperta iron-based hardfacing alloys showed a need for sample dimension reduction due to compressive loads that could not be met by a 50 kN maximum capacity mechanical testing system. The preliminary tests showed compressive strengths exceeding 2340 MPa. Samples of the current …


Mechanical Testing Of Multi-Construction Composite Tubes For Use In Fly Fishing Rods, Macormik Hopen Jun 2015

Mechanical Testing Of Multi-Construction Composite Tubes For Use In Fly Fishing Rods, Macormik Hopen

Materials Engineering

A testing protocol was established for measuring the flexure properties of thin-walled tubes constructed of a composite mixture of glass and carbon fibers and epoxy resin for use in Fly Fishing rods. Standard three point bend tests were conducted in accordance with ASTM standard D7329-13 with a span length of six inches. All samples were of the sample length and diameter, allowing direct comparison of the maximum loads reached before failure, which are directly indicative of the Modulus of Rupture (MOR). Two constructions were tested both containing the same unidirectional fiber but with different support structure. These tubes were tested …


Improving Product Design By Predicting Flexural Strength Of A Honeycomb Core Sandwich Panel Composite Using Ply Tensile Strength, Justin Lui, Javal Patel Jun 2015

Improving Product Design By Predicting Flexural Strength Of A Honeycomb Core Sandwich Panel Composite Using Ply Tensile Strength, Justin Lui, Javal Patel

Materials Engineering

The use of composite sandwich panels has increased in the aerospace industry. Prediction of a theoretical composite construction's flexural properties is important for efficient composite product designs. Utilizing the four point flexure geometry defined by Zodiac Aerospace, Santa Maria, CA, a mechanical model was derived to predict the flexural behavior of a theoretical honeycomb core sandwich composite using laminate tensile properties. The most common failure mode of Zodiac Aerospace’s four point bend test is a failure in tension of the bottom laminate. Given this information, ASTM D3039 (Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials) was chosen …


Tensile Test Design To Measure Interlayer Adhesion In Investment Casting Shells For Spalling Mitigation, Shelby Boyd, Alex Miller, Jameson Senger Jun 2015

Tensile Test Design To Measure Interlayer Adhesion In Investment Casting Shells For Spalling Mitigation, Shelby Boyd, Alex Miller, Jameson Senger

Materials Engineering

We designed a tensile test fixture for a 112 lbf capacity Instron load frame that imparts a normal force on the face of a button epoxied to an investment casting shell sample, delaminating the shell area attached to the button. Using a green standard shell (Group 1), a partially fired standard shell (Group 2), and a green shell with a different third coat (Group 3), we verified that the fixture can measure differences in strength between sample groups. We attached steel buttons to leveled samples with 0.05 mL of Hysol-Loctite 9340 epoxy, let it cure for 48 hours, and tested …


Measuring And Increasing The Suspension Time Of Lanthanide Oxysulfide Particles With Modifiers Via Fluorescence For Use In Anti-Counterfeiting Applications, Joe Dei Rossi, Tyler Dinslage, Tyler Schelling Jun 2015

Measuring And Increasing The Suspension Time Of Lanthanide Oxysulfide Particles With Modifiers Via Fluorescence For Use In Anti-Counterfeiting Applications, Joe Dei Rossi, Tyler Dinslage, Tyler Schelling

Materials Engineering

No abstract provided.


Investigating The Cause Of Unique Mechanical Behavior In Platinum Alloy Guidewire Tips, Evan Borgeson, Alfred Rosen Jun 2015

Investigating The Cause Of Unique Mechanical Behavior In Platinum Alloy Guidewire Tips, Evan Borgeson, Alfred Rosen

Materials Engineering

The platinum alloy used by Abbott Vascular in guidewire tips exhibits a yielding behavior characterized by an abrupt transition from elastic to plastic zones and high ductility. This yielding behavior was hypothesized to be a result of one of three structural phenomena: ordering, solute strain aging, or interstitial strain aging. To test for these strengthening mechanisms in the wire, X-ray diffraction analysis, heat treatments, and tensile testing were completed. The wire has a diameter of 0.0025 inches and was supplied in two forms, the final stress relieved state, and as-drawn from the production line. Heat treatments were performed at 130 …


Electrochemical Testing Of Aluminum-Lithium Alloys 2050, 2195, And The Current Aerospace Industry Standard 7075 To Measure The Galvanic Corrosion Behavior With Ti-6al-4v, Trent Duncan, Kevin Knight Jun 2015

Electrochemical Testing Of Aluminum-Lithium Alloys 2050, 2195, And The Current Aerospace Industry Standard 7075 To Measure The Galvanic Corrosion Behavior With Ti-6al-4v, Trent Duncan, Kevin Knight

Materials Engineering

This project aimed to characterize the electrochemical behavior of four different aluminum alloys, and determine how much galvanic corrosion would occur when each alloy was coupled to Ti-6Al-4V. The particular alloys tested were 2050-T3, 2050-T852, 2195-T852, and 7075-T7352. These alloys were tested to determine the effects of aging, and adding lithium, to the corrosion behavior of aluminum alloys. Potentiodynamic polarization curves were generated using the Parstat 2273 potentiostat in accordance with ASTM standard G5, and corrosion analysis software was used to produce Tafel fit lines, which determined the open circuit potential (Ecorr) of each sample. Nine tests were …


Analysis Of Compression Creep Deformation Of 7050 Aluminum Large Scale Open Die Forgings During The Solution Heat Treatment Process, Ashley Lopez, Elysha Cole Jun 2015

Analysis Of Compression Creep Deformation Of 7050 Aluminum Large Scale Open Die Forgings During The Solution Heat Treatment Process, Ashley Lopez, Elysha Cole

Materials Engineering

A stress, ranging from 104.17 to 166.67 psi, was applied to 0.5 in diameter cylindrical samples of 7050 aluminum using a manufactured fixture that applies stress using an indenter with a diameter of 0.127 in. The stress range used replicates the stresses produced on large scale forgings weighing up to 4000 lbs. We chose a maximum, medium and low stress as our stress parameters. The samples were placed into the fixture for stability then placed in a furnace heated to 890°F which is the solution heat treatment temperature for 7050 aluminum. The heat treatment times varied between 4 and 24 …


Characterization Of Laser Deposited Ti-6al-4v To Nb Gradient Alloys, Clincy Cheung Jun 2015

Characterization Of Laser Deposited Ti-6al-4v To Nb Gradient Alloys, Clincy Cheung

Materials Engineering

An alloy was fabricated with Ti-6Al-4V and Nb powder using laser deposition (LD) to form a compositional gradient. The gradient was deposited, starting with Ti-6Al-4V powder, onto a forged Ti-6Al-4V substrate in an Argon environment. Niobium (Nb) composition increased by 4-at.% with each layer deposited until the composition reached 100-at.% Nb. This process yielded steep thermal gradients and affected the microstructure and mechanical properties across the compositional gradient. To observe the microstructural changes in the alloy, an etched gradient was viewed with optical microscopy at 1000x, where the grain structure was observed to be an acicular α phase at 100-at.% …


Minimizing Sheet Resistance Of Organic Photovoltaic Cell Top Contact Electrode Layer: Silver Nanowire Concentration Vs. Conductive Polymer Doping Concentration, Caitlyn Cook Jun 2015

Minimizing Sheet Resistance Of Organic Photovoltaic Cell Top Contact Electrode Layer: Silver Nanowire Concentration Vs. Conductive Polymer Doping Concentration, Caitlyn Cook

Materials Engineering

The top contact electrode layers of nine organic photovoltaic cells were prepared with two varying factors: three Silver nanowire (AgNW) densities deposited on a conductive polymer doped with three concentrations. Silver’s low sheet resistance of 20-Ω/sq is hypothesized to lower the sheet resistance of the anode layer and thus enhance the overall efficiency of the cell. Four-point probe measurements indicated that increasing AgNW density in the top contact electrode layer of an organic photovoltaic cell significantly reduces sheet resistance from 52.2k-Ω/sq to 18.0 Ω/sq. Although an increase in doping concentration of the conductive polymer reduced sheet resistance in low AgNW …


Analysis Of Shear Strength Variance Of Ph 15-7 Mo Blind Rivet Stems For Aerospace Applications, Miles Macarthur, Kent C. Majewski Jun 2015

Analysis Of Shear Strength Variance Of Ph 15-7 Mo Blind Rivet Stems For Aerospace Applications, Miles Macarthur, Kent C. Majewski

Materials Engineering

This project attempts to reduce manufacturing costs incurred to Cherry Aerospace by variance in material properties. To track and predict the shear strength of PH 15-7 Mo stainless steel rivet stems throughout the heat treatment process, samples were taken from several steps in the manufacturing process and experimental heat treatments were performed across a range of temperatures. The supplied rivet stems were heat treated for four hours at temperatures from 520°C to 560°C, in increments of 10°C. Double shear testing in accordance with ASTM 1312-13A revealed that there is no apparent correlation between the strength of the supplied wire and …


Measuring Performance Of Paint Coating Via Laboratory And Field Testing, Eugene Leung, Rocco Lattanzio Jun 2015

Measuring Performance Of Paint Coating Via Laboratory And Field Testing, Eugene Leung, Rocco Lattanzio

Materials Engineering

No abstract provided.