Oxidation resistance and mechanical properties of Laves phase reinforced Cr in-situ composites

Two-phase Cr(X)-Cr2X (X= Nb, Ta) in-situ composites are of interest for hig h-temperature applications due to their high melting points and potential f or high-temperature strength. A six cycle, 120 h, 1100 degreesC cyclic oxid ation screening test was used to evaluate potential for high-temperature ox idation resistance of several Cr(X)-Cr2X in-situ composites. Alloys based o n the Cr-Ta system near the Cr(Ta)-Cr2Ta eutectic exhibited superior oxidat ion resistance compared to corresponding alloys based on the Cr-Nb system. The binary Cr-Ta alloys were also found to exhibit a moderate degree of roo m-temperature fracture toughness, in the range of 9-10 MPa rootm. It was co ncluded that the Cr(Ta)-Cr2Ta alloys are a promising base for future high-t emperature intermetallic alloy development efforts. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.