EFFECT OF Mn AND Si ON NOTCH SENSITIVITY OF AN Fe-Ni BASE SUPERALLOY

The effect of Mn and Si contained on the notch sensitivity of an Fe-Ni base superalloy has been studied. It was shown that the overabundant contents of Mn and Si lead the alloy to notch sensitivity which can hardly be improved even by heat treatment. Analysis and observation under electron microscope indicated that it seems to attribute the notch sensitivity of the alloy to the film-like boride along the grain boundaries substantially.