The High Temperature Deformation Behavior of the Wrought Superalloy 718
Analytical Science and Technology / Analytical Science and Technology, (P)1225-0163; (E)2288-8985
1996, v.9 no.2, pp.179-191
Na, Y.S.
Choe, S.J.
Kim, H.M.
Na,
Y., Choe,
S., &
Kim,
H.
(1996). The High Temperature Deformation Behavior of the Wrought Superalloy 718. , 9(2), 179-191.
Abstract
In order to understand the high temperature deformation behavior of superalloy 718, a rotating grade 718 alloy has been compression tested to about 0.7 upset ratio at $927{\sim}1066^{\circ}C$ temperature range and $5{\times}10^{-4}{\sim}5{\times}10^0sec^{-1}$ strain rate. The maximum flow stress was increased with increasing strain rate, and similar behavior was observed with decreasing temperature. At low temperature and high strain rates other than $5{\times}10^{-1}sec^{-1}$, strain softening was occurred mainly by dynamic recovery and deformation twinning processes, while at high temperature and low strain rates strain softening was offseted by dynamic recrystallization. At $5{\times}10^{-1}sec^{-1}$, strain hardening was occurred due to work hardening of the dynamic recrystallized grains. Strain rate sensitivity, m, was varied with strain rates. In the case of lower strain rate tests, m was measured as 0.3 and it was observed that the deformation was mainly controlled by dynamic recrystallization. At higher strain rate, m was lowered to 0.1 and the deformation was controlled by the dynamic recovery and the deformation twinning processes.
- keywords
-
Superalloy 718,
dynamic recovery,
dynamic recrystallization,
defromation twin