Engineering Commons^™

Discontinuous Recycled And Repurposed Carbon Fiber Reinforced Thermoplastic Organosheet Composites, Philip R. Barnett

Doctoral Dissertations

There is a significant need for low cost, high volume composites in the automotive industry to aid in vehicle lightweighting and safety. The current state-of-the-art severely compromises the mechanical properties of composites to achieve cost and cycle time goals. In this dissertation, a novel composite format, termed discontinuous carbon fiber organosheets, using recycled and repurposed carbon fibers in a thermoplastic matrix is developed and studied. Unlike traditional composites, the long fiber length and rapid processing time yield mechanical properties and cycle times competitive with automotive metals.

Several studies were performed to characterize this new material format. First, samples were manufactured …

Development Of A Novel Casting Alloy Composed Of Aluminum And Cerium With Other Minor Additions, Zachary Cole Sims

Doctoral Dissertations

Eutectic casting alloys of aluminum and cerium are a recent discovery and early research describes an alloy with great potential to meet the growing demand for a lightweight, economical, high specific strength material for use in high-temperature or extremely corrosive environments. The broad application of aluminum alloys across industry sectors is driven by their collection of balanced properties including economical cost, high specific strength, and flexibility of their production pathways. Additionally, their high corrosion resistance makes them a good choice for structural materials. Despite this, the push to use aluminum alloys in ever more extreme environments with higher temperatures, stresses, …

Design And Development Of Strong And Ductile Single Bcc Refractory High-Entropy Alloys For High-Temperature Applications, Chanho Lee

Doctoral Dissertations

The objectives of this proposed study are to (1) design and develop single BCC phase refractory high-entropy alloys (HEAs) for the high-temperature applications, (2) investigate the deformation mechanisms of refractory HEAs, (3) improve an integrated approach, coupling focused experiments and theoretical modeling, to design, discover, and develop HEAs, and (4) understand the alloy design-microstructure-property-performance links underlying the mechanical behavior of refractory HEA systems for gas-turbine applications

A traditional alloy system generally includes one or two principal elements that form the matrix with other additional elements, e.g., iron or aluminum alloys, to strengthen some specific properties, such as strength and corrosion …

Cracking And Earing Phenomenon In Deep-Drawn Stainless Steel Alloys: Role Of Transformation Kinetics, Microstructure, And Texture, Peijun Hou

Doctoral Dissertations

The enhancement of formability of advanced high-strength TRIP-assisted steel alloys is a challenging assignment for industrial application due to the cracking phenomenon. The critical factor governing the cracking behavior is residual-stress concentration resulting from the inhomogeneous plastic deformation and microstructural evolution during the forming processes. Martensitic phase transformation kinetics, constituent phases, and crystallographic texture in TRIP-assisted steel alloys are correlated to the microstructure evolution, resulting in phase-specific stress concentration. In the current study, we are aiming at understanding the fundamental mechanisms responsible for the cracking phenomenon and thus improving the formability of TRIP-assisted steel alloys. Four stainless steel (SS) alloys …