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Full-Text Articles in Engineering
Solvent Analysis Of Phenolic Resin Glass Fiber Reinforced Prepreg During Out-Time, Sixin Zhai, Crystal Ipong
Solvent Analysis Of Phenolic Resin Glass Fiber Reinforced Prepreg During Out-Time, Sixin Zhai, Crystal Ipong
Materials Engineering
Phenolic resin glass fiber reinforced prepregs are highly suitable for airplane interior components due to their high fire resistance, high temperature performance, and low-density characteristics. Safran Cabin seeks to improve their storage of the phenolic resin prepreg during their manufacturing process. The issues the company faces are the occasional delamination of prepreg laminas or the loss of tackiness rendering the lamina unfit for use. The area of investigation was determining the weight loss of volatiles during out-time. The term “out-time” consists of the time the prepreg experiences in transit, on the shop floor, and in short-term temperature-controlled storage. Simulated storage …
Development Of Low Cost, Environmentally Friendly And High Strength Carbon Foams From Bread And Cake, Laura Mountain-Tuller
Development Of Low Cost, Environmentally Friendly And High Strength Carbon Foams From Bread And Cake, Laura Mountain-Tuller
Materials Engineering
Carbon foam is a high niche material that consists of a highly porous, three-dimensional cellular network that is characterized by extremely high strength-to-weight ratios and low thermal conductivity. Due to these properties, carbon foams excel in structural and thermal applications, especially in the aerospace industry. Typically, carbon foams are formed through a heating process called pyrolysis of polymer precursors with high carbon content. This process is done at high temperatures in an oxygen free environment. These precursors are expensive to make and use toxic chemicals to produce, therefore, there is a push to find an environmentally friendly and cost-effective method …
The Natural Aging Behavior Of Open-Die-Forged 7050 Aluminum Alloy, Casey J. Madsen, Joseph J. Redfearn
The Natural Aging Behavior Of Open-Die-Forged 7050 Aluminum Alloy, Casey J. Madsen, Joseph J. Redfearn
Materials Engineering
The aging response of open-die-forged 7050 aluminum was studied at various temperatures. This is of interest because the alloy can potentially crack during stress relief if it ages after its heat treatment. Natural aging limits the ductility enough to potentially cause cracking and is combatted by placing the forgings in freezers. This experiment shows which temperatures successfully inhibit aging in the forgings. The goal was to develop a maximum time that a sample can be stored at certain temperatures before the forgings have naturally aged. The samples were first solution heat treated then water-quenched. Next, the samples were stored at …
Straightening Of Investment Casting Ni-Based Superalloys, Silvia Squillaci, Janessa Cabrera
Straightening Of Investment Casting Ni-Based Superalloys, Silvia Squillaci, Janessa Cabrera
Materials Engineering
Samples belonging to four different designs of afterburner flaps, available in the as-cast, solutionized and aged conditions, underwent 4-point bend testing to fracture to investigate straightening. The average maximum load values of the second design samples in the as-cast, solutionized and aged conditions were respectively 33 kN, 29 kN and 27 kN. Regarding the fourth design samples, the average maximum load for the as-cast, solutionized and aged conditions were respectively 23 kN, 28 kN, and 25 kN. The other parameter measured during testing was the maximum extension at fracture. All as-cast samples belonging to the second design fractured at values …
Life Cycle Assessment Of Paper Versus Electronic Assignment Submission In Cal Poly's Materials Engineering, Patrick Mcdonnal
Life Cycle Assessment Of Paper Versus Electronic Assignment Submission In Cal Poly's Materials Engineering, Patrick Mcdonnal
Materials Engineering
Both hard and soft copy submission of assignments make an impact on the environment to produce the final product in terms of energy consumption and carbon emissions; an investigation was conducted as to which method is less environmentally impactful. Student disposition towards each assignment submission method was also investigated because it is associated with learning efficacy. A survey was conducted in Cal Poly’s Materials Engineering Department to determine the contributing components to the environmental impact of paper and electronic assignments, as well as the students’ disposition towards each of them. Contributing components are man-made products used by a student to …
An Investigation Of Incipient Melting During Solution Heat Treatment Of 7050 Aluminum Forgings And Its Effect On Corrosion Properties, Thomas Kilkenny
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 …
Effects Of Initial Forging Temperature, Cooling Rates, And Carbon Content On Primary Alpha Formation In Ti-6al-4v, James Tillman, Hui Wei
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 …
An Investigation Into The Properties And Fabrication Methods Of Thermoplastic Composites, Ann E. Livingston-Peters
An Investigation Into The Properties And Fabrication Methods Of Thermoplastic Composites, Ann E. Livingston-Peters
Master's Theses
As applications for thermoplastic composites increase, the understanding of their properties become more important. Fabrication methods for thermoplastic composites continually improve to match designs specifications. These advanced thermoplastics have begun to show an improvement in mechanical properties over those found in thermoset composites commonly used in industry. Polyaryletherketones (PEK) have high service temperatures, good mechanical properties, and improved processing capabilities compared to thermoplastics used in the past making them important to the aerospace industry. The wide range of types of PEK make them suitable for a variety of applications, but selection of specific chemistries, processing parameters, and composite stack-ups determine …
The Design And Fabrication Of An Electrostatically Actuated Diaphragm With A Silicon-On-Insulator Wafer, Elizabeth L. Brooks
The Design And Fabrication Of An Electrostatically Actuated Diaphragm With A Silicon-On-Insulator Wafer, Elizabeth L. Brooks
Master's Theses
Electrostatically actuated silicon membranes were designed, modeled, fabricated, and characterized. The intended application was for use in a microspeaker. Fabrication issues necessitated the use of thick diaphragms with a large gap between the electrodes. The devices did not function as speakers but did show actuation with a high DC voltage. Device dimensions were chosen by examining membrane mechanics, testing the processing steps required for device fabrication, and modeling with COMSOL. Several adhesives were researched to fabricate the device sidewalls, including BCB, PMMA, and TRA-Bond F112. A method for patterning PMMA through photolithography was found using a scanning electron microscope. Masks …
Strength Testing And Material Characterization Of Cactus Spines, Mary Cooper, Jeff Goldstein, Thomas Tarlton
Strength Testing And Material Characterization Of Cactus Spines, Mary Cooper, Jeff Goldstein, Thomas Tarlton
Materials Engineering
Twelve different species of cactus spines from 6 different genera were collected from living specimens and maintained in a dry storage environment. Spines from each species underwent 3-point bend testing, XRD testing, and SEM imaging. XRD analysis was used to verify the presence of cellulose whisker like nanocrystals and to calculate the percent crystallinity of each spine. SEM images were captured of fracture surfaces at viewing angles of 90° and 45° relative to the fracture surface, with magnifications ranging between 150x and 4,000x. A total of six spines from each species were tested in three point bending using a high-resolution …
An Investigation Of Arabinan And Cellulose Based Nano-Composite Fabrication Methods, Marianne Smithfield, Carl Petterson, Robert Miller
An Investigation Of Arabinan And Cellulose Based Nano-Composite Fabrication Methods, Marianne Smithfield, Carl Petterson, Robert Miller
Materials Engineering
Microcrystalline cellulose was converted into nanocrystalline cellulose via an acid hydrolysis procedure. Scanning electron microscopy (SEM) was employed to measure the particle size and thus the effectiveness of acid hydrolysis. The nanocrystalline cellulose was poured through a 0.2μm filter to isolate the particles of ideal size. The nanocrystalline cellulose samples were stored in dimethylformamide (DMF) to prevent mold growth and agglomeration upon drying. Numerous composite samples were created by dissolving the arabinan in a solvent, suspending cellulose in the arabinan solution, and then drying the sample. Casting was performed in a silicon mold to allow sample removal without damage. Initial …
Effect Of Carbon On Primary Alpha Percentage In Ti-6al-4v As Temperature Approaches The Beta Transus, Kyle Savage
Effect Of Carbon On Primary Alpha Percentage In Ti-6al-4v As Temperature Approaches The Beta Transus, Kyle Savage
Materials Engineering
Some Ti-6Al-4V forgings require a specific amount of α phase known as primary α in the finished product. The percentage of primary α is dependent on how close to the beta transus temperature forging is conducted. The beta transus temperature is affected by certain alloying elements. Carbon is one of the elements known to increase the beta transus temperature. Since each Ti-6Al-4V ingot contains varying amounts of carbon, testing on a variety of chemistries needs to be conducted. Cubes approximately 0.5 inches from low, medium, and high carbon chemistries were heat treated at temperatures below the beta transus in 18 …
A Design Methodology For Buoyant Prescription Sunglasses, Katherine Burzynski
A Design Methodology For Buoyant Prescription Sunglasses, Katherine Burzynski
Materials Engineering
As a means to develop fashionable, buoyant prescription sunglasses, this project focused on identifying a system of lens and frame materials that yield sunglasses that float in water. There was an emphasis on developing a product that could be integrated into the current sunglass market. The term fashionable is used to define a sleek frame style that does not require attaching additional floatation. This methodology relies on the relationships between the strength of the user’s prescription and the volume of the desired sunglass frame style. This relationship was verified through buoyancy testing. This testing included varying the lens material in …
The Effects Of Heat Treatment On The Grain Growth, Phase Evolution, And Hardness Of Newly Developed Steel-Based Hardfacing Alloys For Industrial Applications, Renee Kuzniar
Materials Engineering
Steel-based hardfacing alloys are welded onto the outside diameter of tool joints in three beads with a slight overlap between welds for underground drilling to prolong the tool joints’ life. Current hardfacing alloys have a shortened life due to cracks occurring in neighboring weld beads. To decrease cracking, the effects of composition and heat treatment on the microstructure was investigated on five alloys. Five small arc-melt circular ingots roughly 1.4 x 0.3 inches were produced. Each sample had varying amounts of C, B, Cr, Mn, Mo, Nb, Si, Ti, V, and W. The carbon levels in the alloys were .91wt%, …
Grain Size Control In Post-Forged C263 Seamless Rolled Rings, Christopher Smith
Grain Size Control In Post-Forged C263 Seamless Rolled Rings, Christopher Smith
Materials Engineering
Seamless rolled rings of C263 superalloy were forged by Carlton Forge Works in Paramount, CA and sectioned for mechanical testing. The as-forged ring sections were then machined into tensile samples. To simulate cold working done after Carlton’s forging process, the C263 tensile samples were strained using an Instron tensile tester to 1, 3, 5, 7, and 9% plastic strain. These tensile samples were then solution treated at 2100°F for 30 minutes and water quenched before being aged at 1470°F for 8 hours and air cooled, following Carlton Forge Works’ heat treatment process. The gauge length sections were metallographically prepared and …
Comparison Of Polyurethane And Polysiloxane Coating Systems In Marine Environments, Jake Jarman, Jessica Salvatin
Comparison Of Polyurethane And Polysiloxane Coating Systems In Marine Environments, Jake Jarman, Jessica Salvatin
Materials Engineering
This project investigates the performance benefits of polysiloxane and polyurethane coating systems for corrosion protection in marine environments. PPG Industries Amercoat 450H and International Paint Interthane 990HS were the polyurethane topcoats tested. PPG Industries Ameron PSX 700 (New Blend) and International Paint Interfine 878 were the polysiloxane topcoats tested. Each coating was sprayed onto carbon steel panels that were prepared through hand blasting with glass beads. Scribed and unscribed panels were tested in a salt fog chamber for 1,200 hours according to ASTM Standard B0117-11 and in a UV/Humidifier for 1,650 hours according to ASTM Standard D4587-11. Panels were tested …
Corrosion Of Stainless Steel 316l And Astm F75 Cobalt Chromium Alloy During Immersion Testing In Silver Salt Solutions, Meagan Higgins
Corrosion Of Stainless Steel 316l And Astm F75 Cobalt Chromium Alloy During Immersion Testing In Silver Salt Solutions, Meagan Higgins
Materials Engineering
This study evaluates the potential effects of silver salts on biocompatible metals used for prostheses during the chemical reduction process to produce a silver antimicrobial layer on the metal’s surface. Samples of two biocompatible metals were obtained: Stainless Steel 316L and ASTM F75 Cobalt Chromium Alloy. Three different silver salts were also acquired: silver nitrate, silver sulfadiazine, and silver chloride. Specimens of each metal were cut to size using a 4-1/2 inch aluminum oxide, 40 grit, cut off wheel for metal, attached to a Dewalt Angle Grinder. The biocompatible metal samples were then subject to either Solution 1, water with …
Analysis Of Failed Forging Saddling Mandrels And Process Improvements For Increased Mandrel Lifespan, Brock Costalupes
Analysis Of Failed Forging Saddling Mandrels And Process Improvements For Increased Mandrel Lifespan, Brock Costalupes
Materials Engineering
This project seeks to increase the lifespan of steel mandrels used by Schlosser Forge in the saddling process, which is part of the production of forged rings for the aerospace and power generation industries. All saddle mandrel samples were taken from used 4340 steel mandrels. Hardness profiles were measured across rectangular bars cut from the transverse direction of a completely fractured piece of a 7″ diameter mandrel. The hardness near one outer surface of the tested bar was 36 HRC and gradually decreased to 30.5 HRC at the opposite surface. Macroscopic examination of the primary fracture surface along with light …
An Exploratory Investigation Into How Cold Working Can Affect The Acoustic Performance Of Thin Aluminum Foil In A Ribbon Microphone, Alexander (Alex) Stanley
An Exploratory Investigation Into How Cold Working Can Affect The Acoustic Performance Of Thin Aluminum Foil In A Ribbon Microphone, Alexander (Alex) Stanley
Materials Engineering
Ribbons of 4 μm thin 99.1% pure aluminum foil were cut and corrugated to replace the stock ribbon in an Apex 205 ribbon microphone. Prior to corrugation, half of the ribbons were sandwiched between two KimWipes and two pieces of cardstock then hammered to impart strain hardening. Each ribbon was placed into the microphone capsule and the frequency response of each ribbon was measured. A 10 second sine sweep from 20-20,000 Hz was played through a KRK Rokit 5 speaker and recorded through a ribbon microphone placed 6 inches away from the speaker cone. The signal generated by the ribbon …
The Synthesis And Characterization Of Gold And Silver Nanoparticles In Formal And Informal Settings, Mathew Wynn
The Synthesis And Characterization Of Gold And Silver Nanoparticles In Formal And Informal Settings, Mathew Wynn
Materials Engineering
Silver nanoparticles were synthesized through the reduction of AgNO3 using NaBH4. The borohydride anions were adsorbed onto silver nanoparticles. The repelling forces of the borohydride anions prevented the aggregation of particles, but the addition of an electrolyte or agitation induced aggregation. A yellow hue was given off by the silver nanoparticle sol that, using a spectrophotometer, had plasmon resonance at 386 nm. The silver nanoparticles were estimated to be 10 to 20 nm in diameter. Gold nanoparticles were synthesized through the reduction of HAuCl4 using Na3C6H5O7. The gold nanoparticle sol gave off a red hue that had plasmon resonance at …
Design And Development Of An Interactive Materials-Based Learning Kit For K-4 Grade Levels, Thomas Agasid, Santiago Caceres, James Woodhead
Design And Development Of An Interactive Materials-Based Learning Kit For K-4 Grade Levels, Thomas Agasid, Santiago Caceres, James Woodhead
Materials Engineering
The Materials Safari Adventure kit was designed to help introduce basic materials concepts to young audiences in kindergarten through fourth grade levels. The primary goal of this project was to design a tool to spark an interest in materials science for young children, while revealing the field of materials science to parents and educators. The final kit design incorporates a safari theme to encourage imagination and promote self-directed learning through the interaction with materials. Materials were selected to showcase a range of properties within three materials classes: metals, polymers, and natural woods. A total of 9 materials were chosen for …
The Effects Of Concentration, Stir Rate, And Processing Temperature On The Iridescence Of Polymethyl Methacrylate Nanoparticles, David Baruela
The Effects Of Concentration, Stir Rate, And Processing Temperature On The Iridescence Of Polymethyl Methacrylate Nanoparticles, David Baruela
Materials Engineering
Synthetic opals were synthesized by creating polymethyl methacrylate (PMMA) nanospheres in order to determine which conditions would create the best iridescent samples. The factors affecting the iridescence were nanosphere concentration, stir rate, and processing temperature. PMMA solutions were made by adding 17 mg of granular azobis to a solution of 16 mL of distilled water with 3 mL of methyl methacrylate (MMA). The solution was stirred at different rates, slow and fast, and different temperatures, 70 °C and 90 °C, under a constant flow of nitrogen gas for 40 minutes until the polymerization reaction was complete. Glass substrates were prepared …
Al2O3 Oxide Morphology For Two Fe-Cr-Al Stainless Steel Foils Used In Gasoline Engine Catalytic Converters, Jennifer Suiter
Al2O3 Oxide Morphology For Two Fe-Cr-Al Stainless Steel Foils Used In Gasoline Engine Catalytic Converters, Jennifer Suiter
Materials Engineering
Corrugated 0.05 in thick strips of Fe-Cr-Al ferritic stainless steel samples with 4% and 6% aluminum were heat treated, and the resulting Al2O3 oxide was analyzed using SEM imaging. Three heat treatment cycles were carried out for each sample. The heat treatments were based on future metal-substrate catalytic converter processing prior to applying the washcoat Each heat treatment started with a 90 minute ramp from room temperature to 538°C and a 32.5 minute ramp from 538°C to 899°C. The three different dwell periods at 899°C were 4 hours, 6 hours, and taking a sample out every hour …
The Design And Fabrication Of A Silicon Membrane For Electrostatic Actuation, Elizabeth L. Brooks
The Design And Fabrication Of A Silicon Membrane For Electrostatic Actuation, Elizabeth L. Brooks
Materials Engineering
An electrostatically actuated silicon membrane was designed and fabricated utilizing a siliconon- insulator wafer. The SOI wafer contains three layers- a 400μm thick “handle” layer of silicon followed by a 2μm thick oxide layer topped with a 20μm thick “device” layer of silicon. The embedded oxide layer acts as an etch-stop during silicon etching, leaving a thin membrane of consistent thickness on the device side. The device dimensions were chosen to provide acceptable membrane deflection predicted by calculations and Finite Element Analysis. A microfabrication process plan was designed to produce thin membranes appropriate for electrostatic actuation. A 700nm layer of …
Correlation Between 90o Tensile And 90o Flexural Properties For Thermoplastic Based Carbon-Fiber Composites, Amy Lautenbach
Correlation Between 90o Tensile And 90o Flexural Properties For Thermoplastic Based Carbon-Fiber Composites, Amy Lautenbach
Materials Engineering
Thermoplastic matrix composites containing carbon fibers and 4 different resins (TP 1-TP 4) were tested in tension with the fibers at 90 degree to the longitudinal axis following ASTM D 3039-00. The tensile strengths varied from 5.07-13.87 ksi with TP 1 as the strongest, and TP 4 as the weakest. SEM images were taken of the fracture surface of the samples to explore the fiber-matrix interaction. The SEM images showed significantly more wetting of the fibers in the higher strength materials. The SEM images of the two stronger materials showed resin coating the fibers even after fracture while the two …
The Effects Of Heat Treatment On Area Percent Porosity And Corrosion Behavior Of High-Nickel Thermal Spray Coatings, Travis Crowe, Alec Guraydin
The Effects Of Heat Treatment On Area Percent Porosity And Corrosion Behavior Of High-Nickel Thermal Spray Coatings, Travis Crowe, Alec Guraydin
Materials Engineering
Samples of two Thermal Spray Coating (TSC) alloys on a low carbon steel substrate were obtained: alloy C276 and Nicko-Shield 200. Specimens of each alloy were subjected to heat treatments at temperatures at 1100° for 60 minutes and 1200° for 10 minutes, with some specimens left in the as-sprayed condition. Three replicates were prepared for each condition. Thin 1” strips were cut using a diamond wafering blade for porosity measurements and 2” x 1” specimens were cut for corrosion testing using a SiC abrasive saw. The porosity specimens were mounted in acrylic resin, polished, and examined using SEM. From these …
The Effects Of Colorant Oxides And Firing Rate On The Nucleation And Growth Of Zinc Silicate Crystals In Crystalline Glazes, Nicolas Coffey
The Effects Of Colorant Oxides And Firing Rate On The Nucleation And Growth Of Zinc Silicate Crystals In Crystalline Glazes, Nicolas Coffey
Materials Engineering
This study looked at the effects of colorant oxides and firing rate on the nucleation and growth of crystals in zinc-based crystalline glazes. One weight percent of iron and copper oxide powders were mixed separately with a zinc-based crystalline glaze. The uncolored glaze along with both colored glazes were applied to test tiles and fired. Two different firing schedules were used with different ramp up firing rates of 165°C/hr (slow) and 205°C/hr (fast). X-ray diffraction (XRD) analysis found both zinc oxide and silica oxide in the raw glaze, which are the main components in the formation of zinc silicate. XRD …
Characterization Of Aluminum-Boron Carbide Particulate Metal Matrix Composites, Eric Blank
Characterization Of Aluminum-Boron Carbide Particulate Metal Matrix Composites, Eric Blank
Materials Engineering
The analysis of die-cast 380 aluminum-boron carbide particulate metal matrix composites (MMC) was performed in order to see if the samples had the required tensile strength of 300 MPa. 10wt% B4C die-cast samples were produced and tested. Half were heat treated to the T6 condition and the others were left as cast. Using ASTM standard B 557M it was found that the average tensile strength for the as-cast samples was 130 MPa and the heat treated samples had a tensile strength of 93 MPa. These values were both lower than expected. The heat treated samples were not expected to have …
Validation Of A Secondary Fabric Supplier And Characterization Of Alternate Cores For Use In The Aptera 2e Sandwich Core Composite, Bryan Rogers
Materials Engineering
Polymer matrix composites’ high strength to weight ratio has made them an ideal material choice for use in lightweight transportation vehicles. Aptera Motors, a company based out of Oceanside, CA, is currently developing a next-generation high efficiency passenger vehicle called the Aptera 2e. The 2e’s body is composed of a sandwich core composite containing laminates of E-glass fibers embedded within an epoxy matrix sandwiched between a polyester hexagonal core. This project looked to validate a secondary fabric supplier for use in Aptera’s composite and characterize the core shear properties of two alternate core materials for future iterations of Aptera’s vehicle. …