Ultrahigh Temperature Composite

The objective of Task II is to optimize the procesing technique of producing HfC, TaC and hafnium tantalum carbide (HfC/TaC) carbon fiber reinforced composites. The proposed research in PHASE II will incorporate several innovations that have been acquiredin Phase I and optimization to achieve strong and tough composites. The most desirable matrix phase to attain high mechnical strength consists of very fine, equiaxed grains. This microstructure is typically produced at higher supersaturation and underwhich surface diffusion is limited. PHASE II aims to achieve these desirable microstructures through process optimization which takes Ta2O5 content to eliminate the undesirable phase transition of HfO2. The estimate of effectiveness of the HfCXOYinterlayer as a diffusion barrier for the systems comprising Cfiber/TaCinterface/HfCmatrix and their combinations will be examined. The ultimate objective of PHASE II is the commercialization of the composite. The commercialization is planned throughdual use applications and specific niche markets for these applications which have been identified. aerospace ultrahigh temperature structuresradiation heat reflectors