pISSN : 1598-706X / eISSN : 2288-8381
한국주조공학회지 (35권6호 170-177)
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
Baig-Gyu Choi†, In-Soo Kim, Jeong-Hyeon Do, Joong-Eun Jung and Chang-Yong Jo
High Temperature Materials Department, Korea Institute of Materials Science, Changwon 51508, Korea
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 η phase, was observed due to segregation near the γ-γ' eutectic in the standard heat-treated specimen. Segregation also induced microstructural evolution near the γ γ-γ' 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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