FABRICATION OF DENSE NICKEL ALUMINIDES BY COMBINED COMBUSTION SYNTHESIS AND IN SITU HOT ISOSTATIC PRESSING

THIS PROPOSAL DESCRIBES A NOVEL PROCESSING TECHNOLOGY WHICH HAS THE POTENTIAL TO ACCELERATE THE DEVELOPMENT OF NICKEL ALUMINIDE COMPOUNDS INTO MATURE MATERIALS FOR ADVANCED APPLICATIONS. THIS TECHNOLOGY COMPRISES A CONTINUOUS, TWO PHASE PROCESS IN WHICH CLOSED POROSITY NICKEL ALUMINIDE BODIES ARE FIRST FABRICATED BY EXOTHERMALLY-DRIVEN SELF PROPAGATING COMBUSTION SYNTHESIS FROM ELEMENTAL POWDER BLENDS OF NI AND AL AND THEN FULLY DENSIFIED IN SITU BY RAPID HOT ISOSTATIC PRESSING (HIP). THIS PROCESS WILL BE INVESTIGATED AND ITS FEASIBILITY DEMONSTRATED FOR BOTH MONOLITHIC AND COMPOSITE (BN-COATED SILICON CARBIDE WHISKER REINFORCED) NI(3)AL MATERIALS.