Creep-Environment Interactions of Alloy 617 at Elevated Temperature
Creep behavior and degradation of creep properties of high-temperature materials often limit the lives of components and structures designed to operate for extended period under stress at elevated temperatures. A nickel-base superalloy, Alloy 617 in particular which is considered as a prospective material for hot gas duct and intermediate heat exchanger in very high temperature gas cooled reactor, was studied for creep properties. Creep tests were carried out under various sustained tensile loadings in air and helium environments at temperature of 800°C, 900°C, and 1000°C. Times for 1% creep strain and creep rupture were taken from the short-term creep tests within 1000 hours. Effect of creep-environment interaction on creep strain and changes in viscous deformation properties by dynamic recrystallization were discussed.