Published online by Cambridge University Press: 10 February 2011
Changes in the microstructure, mechanical properties and corrosion resistance of C-22 alloy were studied systematically as a function of aging temperature and aging time. Aging was performed in the temperature range 260°C to 800°C for times between 0.5 h and 40,000 h. For aging temperatures of 600°C and higher, precipitation of tetrahedral close packed (TCP) phases in C-22 alloy induce a decrease in its mechanical properties and corrosion resistance in aggressive acidic solutions. At the lower aging temperatures, long range ordering (LRO) was observed, which did not produce changes in the chemical resistance of the alloy. Arrhenius extrapolations of the high temperature data predict that C-22 alloy will be thermally stable when exposed to temperatures in the order of 300°C for times higher than 10,000 years.