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Creep Behavior And Deformation Mechanisms Of Spark Plasma Sintered Oxide Ceramics For Aerospace Systems At 1300˚C - 1400˚C, David D. Swanson
Creep Behavior And Deformation Mechanisms Of Spark Plasma Sintered Oxide Ceramics For Aerospace Systems At 1300˚C - 1400˚C, David D. Swanson
Theses and Dissertations
The mechanical behavior of YAG and LuAG was investigated at elevated temperatures. The specific materials investigated in this work include high-purity, polycrystalline YAG, high-purity, polycrystalline LuAG, and two doped variants of YAG: 2at% Yb-doped, polycrystalline YAG and 2at% Er-doped, polycrystalline YAG. Several billets of each material were prepared and processed by means of spark plasma sintering (SPS). Many different sintering parameters were utilized in order to obtain materials with various physical properties and to identify the effects of sintering parameters on the average grain size of the resulting materials. The compressive creep behavior of these materials was investigated at 1300°C …
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1100°C In Air And In Silicic Acid-Saturated Steam, Logan M. Gumucio
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1100°C In Air And In Silicic Acid-Saturated Steam, Logan M. Gumucio
Theses and Dissertations
Innovations in SiC based ceramic matrix composites (CMCs) have yielded exceptional high-temperature properties and performance in aggressive oxidizing environments. These material characteristics provide potential avenues for future advancements in many applications where current metallic alloys perform near their operating temperature limits in a harsh environment. As steam (typically present in these environments) enters through cracks in the matrix of a SiC/SiC composite, it leaches Si and becomes saturated with silicic acid, Si(OH)4, prior to attacking the reinforcing SiC fibers. Therefore, it is paramount that a thorough understanding of the performance and durability of SiC fibers be obtained under …
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1000°C In Air And In Silicic Acid-Saturated Steam, Brian G. Kroeger
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1000°C In Air And In Silicic Acid-Saturated Steam, Brian G. Kroeger
Theses and Dissertations
Advanced SiC/SiC ceramic matrix composites (CMCs) are being considered for a variety of applications. Of interest is their ability to withstand exposure to high temperature in an aggressive oxidizing environment. The presence of steam creates such an environment. As steam traverses across a SiC/SiC composite and through cracks in the SiC matrix, it becomes saturated with silicic acid, Si(OH)4. It is essential to understand the long-term impacts and durability of SiC/SiC CMCs that have been exposed to such a demanding environment. The present research investigated creep of Hi-Nicalon™ S SiC fibers at 1000°C in air and in silicic …
Creep Of Sylramic-Ibn Fiber Tows At Elevated Temperature In Air And In Silicic Acid-Saturated Steam, Kevin B. Sprinkle
Creep Of Sylramic-Ibn Fiber Tows At Elevated Temperature In Air And In Silicic Acid-Saturated Steam, Kevin B. Sprinkle
Theses and Dissertations
Stressed oxidation experiments on Sylramic-iBN fiber tows were performed to evaluate the novel fiber's mechanical performance, creep behavior, and creep mechanisms. This research effort investigated creep response of Sylramic-iBN fiber tows at elevated temperatures in both air and in silicic acid-saturated steam environments. Creep experiments were conducted at creep stresses ranging from 127 to 762 MPa at 400°C and 500°C in order to examine the mechanical behavior of the Sylramic-iBN fiber tows at temperatures below and above the melting point of boria (450°C). Sylramic-iBN fibers are known to have excellent creep resistance, better than most other non-oxide fibers and significantly …
The Effect Of Elevated Temperature On The Inelastic Deformation Behavior Of Pmr-15 Solid Polymer, Chad E. C. Ryther
The Effect Of Elevated Temperature On The Inelastic Deformation Behavior Of Pmr-15 Solid Polymer, Chad E. C. Ryther
Theses and Dissertations
The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at temperatures in the 274-316°C range. The experimental program was developed to explore the influence of temperature on tensile loading, relaxation and creep behaviors of PMR-15. The results demonstrate that the mechanical behavior of PMR-15 exhibits a strong dependence on temperature. During strain-controlled tensile loading, the slope of the stress-strain curve in the quasi-elastic region decreases and the flow stress level decreases with increasing temperature. During relaxation, the amount of the stress drop decreases with increasing temperature. Based on experimental results the Viscoplasticity Based on Overstress …