Deformation Mechanisms in Niobium Silicide-Based Composites

摘要

This report describes a 9-month technical effort involving microstructure analysis and modeling of Nb-silicide in-situ composite creep mechanisms. This report will describe both experimental and theoretical modeling of the constitutive creep behavior of Nb-silicide in situ composites. The motivation for this study was to develop an understanding of the creep behavior of a class of materials that possess a long-term high-temperature capability in excess of current nickel-based superalloys. During this program the creep mechanisms that can be enhanced by modification of the microstructure and properties of the metal and silicide phases of the composite have been studied. This investigation has examined the effect of volume fraction of silicide and strength of the metallic phase on the creep performance of the composites. The effect of alloying additions on single-phase and composite creep behavior has also been investigated. This report will describe both experimental and theoretical modeling of the constitutive creep behavior of Nb-silicide in situ composites.