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.
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Title
Fiber-reinforced Ti₃SiC₂ and Ti₂AlC mAX phase composites
Creators
Charles B. Spencer - DU
Contributors
Michel W. Barsoum (Advisor) - Drexel University (1970-)
Awarding Institution
Drexel University
Degree Awarded
Master of Science (M.S.)
Publisher
Drexel University; Philadelphia, Pennsylvania
Resource Type
Thesis
Language
English
Academic Unit
Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University