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Full-Text Articles in Engineering

The Effects Of Carbon, Boron And Vanadium On The Microstructural Evolution And Hardness Of Steel-Based Hardfacing Alloys, Kyle Rafa Jun 2010

The Effects Of Carbon, Boron And Vanadium On The Microstructural Evolution And Hardness Of Steel-Based Hardfacing Alloys, Kyle Rafa

Materials Engineering

Current hardfacing alloys provide insufficient wear resistance due to either cracking or significant material wear. To increase wear resistance of steel-based hardfacing alloys, the effects of composition on microstructure and hardness were investigated in a progression of alloys. Initially, seven new alloys were prepared varying the carbon-boron ratio with the total constant at 3 wt%. Small arc-melt cast circular ingots were produced roughly 1 x 0.5 inches. Metallography provided insufficient phase magnification, thus a SEM equipped with EDS was used, allowing for microstructure and phase composition analysis. Four distinct carbide phases were found and image analysis software allowed for carbide …


Characterization Of Aluminum-Boron Carbide Particulate Metal Matrix Composites, Eric Blank Jun 2010

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 …


Effects Of A Solution Anneal Quench Delay On The Heat Treatment Response Of Aluminum 2219-T6, Daniel James Filomeo Jun 2010

Effects Of A Solution Anneal Quench Delay On The Heat Treatment Response Of Aluminum 2219-T6, Daniel James Filomeo

Materials Engineering

The ageing response for aluminum 2219-T6 was investigated to determine the effects a quench delay (QD) could have on tensile properties. Before testing commenced, furnace surveys were conducted to ensure they could meet the required temperature stability of + 10˚F (+6˚C). MIL-H-6088 specified a maximum quench delay of 15 seconds for parts thicker than 2.29 mm (0.090 in). An investigation was conducted on how different quench delay times changed the ageing response of T6 heat treated for Al 2219. Heat treatments were performed according to the ASM Handbook. Preliminary tests were performed on 1-1.5 in. cube blocks of Al 2219 …


Validation Of A Secondary Fabric Supplier And Characterization Of Alternate Cores For Use In The Aptera 2e Sandwich Core Composite, Bryan Rogers Jun 2010

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. …


Peak Stir Zone Temperatures During Friction Stir Processing, Sprinivasan Swaminathan, Keiichiro Oh-Ishi, Alexander P. Zhilyaev, Christian B. Fuller, Blair London, Murray W. Mahoney, Terry R. Mcnelly Mar 2010

Peak Stir Zone Temperatures During Friction Stir Processing, Sprinivasan Swaminathan, Keiichiro Oh-Ishi, Alexander P. Zhilyaev, Christian B. Fuller, Blair London, Murray W. Mahoney, Terry R. Mcnelly

Materials Engineering

The stir zone (SZ) temperature cycle was measured during the friction stir processing (FSP) of NiAl bronze plates. The FSP was conducted using a tool design with a smooth concave shoulder and a 12.7-mm step-spiral pin. Temperature sensing was accomplished using sheathed thermocouples embedded in the tool path within the plates, while simultaneous optical pyrometry measurements of surface temperatures were also obtained. Peak SZ temperatures were 990 ⁰Cto 1015 ⁰C (0.90 to 0.97 TMelt) and were not affected by preheating to 400⁰C, although the dwell time above 900 ⁰C was increased by the preheating. Thermocouple data suggested little variation in …


Application Of Self-Determination And Self-Regulation Theories To Course Design: Planting The Seeds For Adaptive Expertise, Linda Vanasupa, Jonathan Stolk, Trevor Harding Jan 2010

Application Of Self-Determination And Self-Regulation Theories To Course Design: Planting The Seeds For Adaptive Expertise, Linda Vanasupa, Jonathan Stolk, Trevor Harding

Materials Engineering

The paper is grounded in the premise that learning occurs within a dynamic system of social and ecological interactions in the learning environment. Our intent is to open the conversation about hose ac, as engineering educators, design effective learning experiences for this dynamic system, particularly in light of the deeply ethical, adaptive expertise required of today's graduates. Drawing from two well-researched theories of psychological development (self-determination and self-regulation), we assert that fostering the engagement and positive growth required for adaptive expertise necessitates a holistic educational approach. This approach requires us to consider both the psychological needs of the learner, and …


The Systemic Correlation Between Mental Models And Sustainable Design: Implications For Engineering Educators, Linda Vanasupa, Roger Burton, Jonathan Stolk, Julie B. Zimmerman, Larry J. Leifer, Paul T. Anastas Jan 2010

The Systemic Correlation Between Mental Models And Sustainable Design: Implications For Engineering Educators, Linda Vanasupa, Roger Burton, Jonathan Stolk, Julie B. Zimmerman, Larry J. Leifer, Paul T. Anastas

Materials Engineering

Many studies have illuminated our understanding of the kinds of competencies and behaviors exhibited by effective designers. Against the backdrop of global challenges made more urgent by unintentional negative impacts of engineered products and systems, however, we are left to deduce that our ways of educating engineering designers is fundamentally flawed. We assert that one can trace the cause of our collective, unintended negative consequences to the mental models of reality that we consciously or unconsciously carry. In this paper, we present the case for developing awareness and facility with mental models. We also suggest an alternate mental model as …