FABRICATION OF A Ni3Al/Al2O3UNIDIRECTIONAL COMPOSITE BY PRESSURE CASTING

Abstract
A gas pressure liquid metal infiltration technique for producing fiber reinforced Ni3Al/Al2O3 and Ni3Al/Al2O3 composites has been described. Composite bars of 9.5 mm diameter, 150 mm long were produced. It was found necessary to add 0.5 at.%Ti to both Ni3Al and NiAl alloys to obtain adequate wetting. There was a strong tendency for liquid metal infiltration along one side of the fibers causing a shift of the fibers to the opposite side. No interface reaction zone was observed at optical magnifications up to 1000X. A composite of Ni3Al containing 33 volume percent of FP fibers fractured at 890 MPa which is approximately 3 times the yield strength of the matrix IC-50(21.73A1-0.34Zr-0.IB-Balance Ni at.%) + 0.5 at. %Ti.