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

Two-phase Cr(X)-Cr(2)X (X= Nb, Ta) in-situ composites are of interest for high-temperature applications due to their high melting points and potential for high-temperature strength. A six cycle, 120 h, 1100 degreesC cyclic oxidation screening test was used to evaluate potential for high-temperature oxidation resistance of several Cr(X)-Cr(2)X in-situ composites. Alloys based on the Cr-Ta system near the Cr(Ta)-Cr(2)Ta eutectic exhibited superior oxidation 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 room-temperature fracture toughness, in the range of 9-10 MPa rootm. It was concluded that the Cr(Ta)-Cr(2)Ta alloys are a promising base for future high-temperature intermetallic alloy development efforts. (C) 2000 Elsevier Science Ltd. All rights reserved.