Effects of Pouring Temperature on the Tensile Properties and Fracture Behavior of Single Crystal Superalloy DD6

Abstract

The effects of pouring temperature on the microstructure and the tensile properties of single crystal superalloy DD6 were investigated. The results show that with the decrease of pouring temperature, the primary dendrite arm spacing increases, and the segregation ratio of main elements decreases obviously. DD6 alloy has the similar tensile behavior under the conditions of the pouring temperatures of 1520°C and 1570°C. The pouring temperature has little influence on the yield and ultimate strengths of DD6 alloy. The yield and ultimate tensile strengths of the specimens with the pouring temperature of 1520°C is little lower than the specimens with the pouring temperature of 1570°C under the testing temperatures at room temperature and 650°C, while the specimens with the pouring temperature 1520°C have higher yield and ultimate tensile strength when the testing temperature is higher than 760°C. The pouring temperature did not have an obvious influence on tensile fracture behavior. It has been observed that the tensile fracture surface belongs to quasi-cleaveage fracture mode at testing temperature of 760°C, but the mix characteristic of quasi-cleaveage fracture mode and dimple fracture mode at the testing temperature of 980°C.