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Full-Text Articles in Engineering
Multi-Scale Investigation Of Microstructure, Fiber-Matrix Bond, And Mechanical Properties Of Ultra-High Performance Concrete, Zemei Wu
Doctoral Dissertations
"The main objective of this study is to provide new insights into enhancing fiber-matrix bond and mechanical properties of ultra-high performance concrete (UHPC). Three main strategies were investigated: 1) use of supplementary cementitious materials; 2) use of nano-particles; and 3) use of deformed fibers. A multi-scale investigation involving the evaluation of non-fibrous UHPC mortar phase (matrix), fiber-matrix interface phase, and then UHPC composite material was undertaken to determine microstructural characteristics, fiber bond to matrix, and key mechanical properties of the UHPC matrix and UHPC. Test results indicate that the incorporation of 10%-20% silica fume effectively improved the fiber-matrix bond and …
Processing, Microstructure, And Mechanical Properties Of Zirconium Diboride-Molybdenum Disilicide Ceramics And Dual Composite Architectures, Ryan Joseph Grohsmeyer
Processing, Microstructure, And Mechanical Properties Of Zirconium Diboride-Molybdenum Disilicide Ceramics And Dual Composite Architectures, Ryan Joseph Grohsmeyer
Doctoral Dissertations
"This research had two objectives: characterization of processing-microstructure-mechanical property relationships of conventional ZrB2-MoSi2 ceramics at room temperature (RT) and 1500⁰C in air, and fabrication of ZrB2-MoSi2 dual composite architectures (DCAs) for use near 1500⁰C. Elastic moduli, fracture toughness, and flexure strength were measured at RT and 1500⁰C for 15 ZrB2-MoSi2 ceramics hot pressed using fine, medium, or coarse ZrB2 starting powder with 5-70 vol.% MoSi2, referred to as FX, MX, and CX respectively where X is the nominal MoSi2 content. MoSi2 decomposed during sintering, resulting in …