MODIFIED AL3TI INTERMETALLIC COATINGS FOR HIGH TEMPERATURE TITANIUM BASE ALLOYS

THE PURPOSE OF THIS RESEARCH PROGRAM IS TO EXPLOIT SOME NEWLY DISCOVERED ALLOY PHASES BASED ON ALLOY-MODIFIED CUBIC AL3TI AS COATING MATERIALS FOR HIGH TEMPERATURE TITANIUM BASED ALLOYS. THE NEW ALLOYS FORMED BY ADDING CHROMIUM OR MANGANESE TO AL3TI READILY FORM A DESIRABLE SCALE OF AL2O3 IN OXIDIZING ATMOSPHERES AND HAVE GREATLY IMPROVED MECHANICAL PROPERTIES AND OXIDATION RESISTANCE (AT 2200 DEG F) OVER EARLIER MODIFICATIONS OF AL3TI. THE PROGRAM WILL USE STATE-OF-THE-ART LOW PRESSURE PLASMA SPRAY TECHNIQUES TO PRODUCE COATINGS ON BOTH CONVENTIONAL AND INTERMETALLIC TITANIUM BASED ALLOYS. POWDERS OF THE COATING ALLOYS TO BE USED IN THE PLASMA SPRAY PROCESS WILL BE PRODUCED BY A STATE-OF-THE-ART ATOMIZATION PROCESS.