Effect of Heat Treatment on Mechanical Properties of U720Li

摘要

The relationship between heat treatment and mechanical property of high strength superalloy UDIMET 720Li has been studied. In this study, the solutioning and cooling rate were changed to alter the γ-grain and cooling γ' sizes. The very low cooling rate was applied to clarity the microstructural change during slow cooling. A specimen, which is applied higher solutioning temperature, shows the high creep resistance while it has significantly low rupture elongation. The cooling γ' size decreases with decreasing cooling rate from solutioning temperature, and further decrease of cooling rate results in the γ-grain growth. Therefore, the tensile and creep strengths decrease when the cooling rate is lower.