CHEMICAL VAPOR DEPOSITION OF TIAL FOILS

EFFECTIVE USE OF INTERMETALLICS IN COMPOSITE AND HONEYCOMB STRUCTURES WILL REQUIRE HIGH STRENGTH, HIGH QUALITY FOIL STARTING MATERIALS. DIRECT FABRICATION OF TIAL FOILS BY CHEMICAL VAPOR DEPOSITION ONTO SACRIFICIAL TAPE SUBSTRATES IS PROPOSED. TWO TECHNIQUES, HIGH TEMPERATURE CHEMICAL VAPOR DEPOSITION FROM MIXED HALIDE VAPORS AND LOW TEMPERATURE CHEMICAL VAPOR DEPOSITION FROM MIXED GASEOUS ORGANOMETALLICS WILL BE USED TO DEPOSIT PURE TI, TI-AL ALLOYS AND PURE AL WITH EMPHASIS ON GAMMA TIAL. THE DEPOSITS WILL BE CHARACTERIZED BY OPTICAL AND SCANNING ELECTRON METALLOGRAPHIC EXAMINATION, X-RAY DIFFRACTION, MICROCHEMICAL ANALYSIS AND MICROHARDNESS TESTING. THE MOST PROMISING OF THE TWO SYSTHESIS TECHNIQUES WILL BE USED TO PRODUCE 0.001-0.003 IN. THICK FOILS RANGING IN COMPOSITION FROM TI45AL55 TO TI55AL45 FOR DETAILED CHARACTERIZATION AND TESTING. ON THE BASIS OF THE RESULTS OBTAINED, CONDITIONS CAN BE ESTABLISHED FOR FOLLOW-ON EFFORTS WHICH WOULD INCLUDEDETAILED MECHANICAL PROPERTY TESTING, PROCESS SCALE-UP, DEMONSTRATION OF SEMI-CONTINUOUS FOIL PRODUCTION, AND PRODUCTION OF NONPLANAR FOIL STRUCTURAL ELEMENTS.