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Please use this identifier to cite or link to this item: http://hdl.handle.net/1860/3302

Title: Fiber-reinforced Ti3SiC2 and Ti2AlC mAX phase composites
Authors: Spencer, Charles B.
Keywords: Materials science;Composite materials -- Creep;Composite materials -- Mechanical properties
Issue Date: 12-Jul-2010
Abstract: It was proposed that reinforcing commercially available MAX phase powders would enhance their high temperature mechanical properties in general, and their creep resistance in particular. Three reaction pairs were studied; Ti2AlC:Al2O3, Ti2AlC:SiC and Ti3SiC2:TiC:SiC. Composites were hot-pressed and hot-isostatic pressed to temperatures as high as 1500 °C. At 1300 °C dense Ti2AlC-alumina composites were fabricated wherein the fibers did not appear to sinter together. At 1500 °C, the alumina fibers agglomerated and sintered together and presumably lost their structural integrity. At these same temperatures, the SiC fibers reacted with the Ti2AlC matrix, losing their integrity as well. It was also shown, through the use of differential scanning calorimetry and x-ray diffraction that Ti2AlC is only kinetically stable at 1500 °C and when the activity of Al in the processing environment is small, Al is lost while Ti3AlC2 and Ti-aluminides are formed. With the Ti3SiC2:TiC:SiC combination, however, processed at 1500 °C, no evidence for a reaction was found. The SiC/Ti3SiC2 interface remained sharp and reaction free. These samples were fully dense. Preliminary results have shown that ≈ 6 vol. % SiC fibers, decreased the creep tensile strain rates at 1100 °C, and increased the times to failure. Based on this work, we conclude that when continuous SiC fibers are incorporated in Ti3SiC2, an increase in the latter’s high temperature creep response will occur and is thus a viable method of extending the life of Ti3SiC2-based materials in high temperature load bearing applications.
URI: http://hdl.handle.net/1860/3302
Appears in Collections:Drexel Theses and Dissertations

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