Using two types of the second generation superalloys CMSX– 4 and DD419
the single crystal blades and plates with the same shape were produced under the same process conditions. The as-cast and solution heat treated microstructures of the blade castings were detected and analyzed. It was found that the γ/γ ′ eutectic fraction in as-cast structure of CMSX– 4 alloy is about 39% higher than that in alloy DD419
in spite of the similar chemical compositions of the both alloys. After solution heat treatment
the residual eutectic in CMSX– 4 alloy was observed to be higher than that of DD419 alloy
revealing more risk to exceed the technical standard. Besides the significant higher eutectic fraction
CMSX–4 exhibits also more non-uniform distribution of eutectic in different blade positions
so that the mechanical properties of the CMSX–4 castings is further negatively influenced.