Effect of S on Solidification Behavior of Cast Superalloy K417G

Abstract

The effects of 0.0001%，0.0018% and 0.0037% S content on the solidification characteristics of K417G alloy were studied by isothermal solidification experiment in the temperature range of 1340-1230 ℃. The results show that S can reduce the solidus temperature of the alloy and enlarge the solid-liquid two phase region. When the S content increases from 0.0001% to 0.0037%， the solidus temperature of the alloy decreases from 1255 ℃ to 1245 ℃. During the solidification process， the S element segregates in the liquid phase and precipitates out as the Y phase in the final solidification zone. And S promotes the enrichment of Al and Cr elements at the solid-liquid interface. At the same isothermal temperature， the increase of S content promotes the increase of the volume fraction of MC carbide，γ+γ΄ eutectic and Y phase， and has little effect on the morphology and precipitation temperature of MC carbide and γ+γ΄ eutectic， but the precipitation temperature of the Y phase is increased from 1230 ℃ to 1240 ℃.

Keywords

• s； isothermal solidification； k417g； element segregation； y phase