ADVANCED CERAMIC FIBERS FOR INTERMETALLIC MATRIX COMPOSITES

INTERMETALLIC COMPOSITES, MOST NOTABLY THE ALUMINIDES, HAVE BEEN IDENTIFIED AS POTENTIAL ENGINE AND STRUCTURAL MATERIALS OFFERING PROPERTIES SUPERIOR TO THOSE OF THE PRESENT NICKELAND COBALT-BASED SUPERALLOYS. UNFORTUNATELY, CURRENTLY AVAILABLE REINFORCEMENTS ARE NOT COMPATIBLE WITH THE ALUMINIDE MATRICES, AND COMPATIBILITY AND/OR COMPLIANT INTERLAYERS MUST BE USED. TREMENDOUS ADVANTAGES CAN BE GAINED BY USING HFN OR TIC MONOFILAMENTS AS REINFORCEMENTS IN AN INTERMETALLIC MATRIX. BOTH HFN AND TIC ARE THERMOCHEMICALLY COMPATIBLE WITH TIAL(3), NIAL, AND FEAL, AND EACH CAN BE PRODUCED IN A FINE-GRAINED MONOFILAMENT. IN THIS PHASE I PROGRAM, ULTRAMET PROPOSES TO DEMONSTRATE THE FEASIBILITY OF PRODUCING HIGH-STRENGTH HFN AND TIC MONOFILAMENTS BY CHEMICAL VAPOR DEPOSITION (CVD), BY OPTIMIZING PROCESSING CONDITIONS AND SUBSTRATE PROPERTIES TO ACHIEVE MAXIMUM STRENGTH AND MATRIX COMPATIBILITY.