Variation of Alloying Element Distribution and Microstructure due to Microsegregation in Ni-base Superalloy GTD 111

니켈기 초내열 합금 GTD 111에서 편석에 의한 합금원소 분포 및 미세조직 변화

Choi, Baig-Gyu;Kim, In-Soo;Do, Jeong-Hyeon;Jung, Joong-Eun;Jo, Chang-Yong

  • Received : 2015.10.30
  • Accepted : 2015.12.04
  • Published : 2015.12.31


Segregation during solidification and homogenization during thermal exposure in GTD 111 were investigated. The microstructures of as-cast, standard heat-treated, and thermally exposed specimens were observed by SEM. A compositional analysis of each specimen was conducted by EDS. The dendrite core was enriched in W and Co, though lower levels of Ti and Ta were observed. An unexpected phase, in this case like the ${\eta}$ phase, was observed due to segregation near the ${\gamma}-{\gamma}^{\prime}$ eutectic in the standard heat-treated specimen. Segregation also induced microstructural evolution near the ${\gamma}-{\gamma}^{\prime}$ eutectic during the standard heat treatment. A quantitative analysis and microstructural observations showed that the thermal exposure at a high temperature enhanced the chemical homogeneity of the alloy.


Ni-base superalloy;Segregation;Thermal exposure;Homogenization


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