Processing, Microstructure, and Properties of Doped and Undoped MgB2 Fibers

A composite consisting of continuous MgB$_{2}$ fibers within an Mg matrix is synthesized by reacting CVD boron fibers with liquid magnesium. Over the reaction temperature range of 700 - 1100 \r{ }C, the reaction time varies by several orders of magnitude. Much slower kinetics are observed for reaction of B fibers doped with C or Ti by co-deposition during the CVD process, which has been shown to improve superconducting properties after reaction to MgB$_{2}$. The reaction times, resulting microstructures, and superconducting properties are compared for both doped and undoped fibers.