ABSTRACT
The elastic properties of materials are of both practical and fundamental importance. In engineering design, for example, the elastic moduli are of primary use in relating stresses and strains expected during service in structures, machines, and the like. On the other hand, in materials science the elastic constants (stiffnesses Cij and compliances S;j) are related to fundamental studies of interatomic forces, thermal expansion, thermoelastic effects, Debye temperature, creep, fracture mechanics, and other areas. Research and development efforts on dispersionhardened alloys have focused intently on providing long-term, high strength at elevated temperatures. Indeed, there is renewed interest in these materials in view of the severe operating conditions expected for the next generation of aircraft, such as the proposed hypersonic vehicles. Although there has been considerable progress in developing alloys that show good strength, oxidation resistance, and creep resistance, relatively little attention has been given to measurements of elastic constants in dispersion-strengthened alloys. This is understandable in view of the degree of difficulty of making measurements of elastic moduli at temperatures above 1000 K for any material.
