Dependence on the Base Element, the Carbide-Former Element and of the Carbide’S Density of the High Temperature Creep Behavior of MCContaining Superalloys

Abstract

The carbides reinforcing cast superalloys are the most often chromium carbides or tantalum carbides (TaC), the second ones being preferred for very high temperature. In this work, three chromium-rich alloys based on Fe, Ni and Co, containing either TaC carbides in unusually high quantity, or unusual HfC carbides were cast and subjected to 3-points bending tests at 1200°C under constant load in order to specify and compare their creep behavior under 20 MPa. The best alloy in this field appeared to be the cobalt-based one reinforced with interdendritic eutectic HfC carbides. After comparison with a Co-25Cr-0.5C-7.5Ta alloy, known for its high strength at 1200°C, this alloy confirmed its great interest for uses at elevated temperature under flexural or tensile stress.