1. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China;
2. Wedge Central South Research Institute Co., Ltd., Shenzhen 518045, China
Abstract: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.