OS7-07 異結晶許容型単結晶超合金YH61の機械的特性と鋳造性(OS7 高温・高效率・発電・エネルギー貯蔵技術)

抄録

Mechanical properties as well as castability of grain boundary resistant Ni-base single crystal superalloy YH-61 are discussed in this paper. YH-61 was developed with being intended for large single crystal buckets and vanes of power generation gas turbines and it realized not only higher casting yield or lower cost but also reliability of grain boundaries as a result of increasing grain boundary strength. Mechanical properties (tensile properties, creep strength and low cycle fatigue properties) were equivalent to the second-generation single crystal superalloy CMSX-4. The result of evaluating misorientation specimens showed that misorientation up to 10° could be considered as substantial single crystal because misorientation up to 10° showed same deformation behavior as single crystal. Low cycle fatigue strength of YH-61/DS was also equivalent to that of CM247LC DS. Trial castings of sample buckets and vanes by using YH-61 showed higher castability of YH-61.