MODEL FOR COARSENING OF SDAS AND ITS VERIFICATION IN MULTICOMPONENT SC SUPERALLOYS
(403 Research Group; Northwestern polytechnical University; Xi’an70072)
Abstract: Based on a general relationship of secondary dendrite arm spacing(SDAS)λ2 to solidification time t:λ23=k0t,a dependence of λ2 on thermal gradient and solidification rate has been presented by assumption of paraboloidal dendrite tip. With the model, secondary dendrite arm spacings predicted for multi component super alloy DD8 and PWA-1480 were in conformity with experimental data.
Key words: secondary dendrite arm spacing directional solidification SC superalloy