|About this Abstract
||MS&T23: Materials Science & Technology
||Advanced Materials for Harsh Environments
||Effect of Heat Treatment on Grain Boundary Characteristics and Intergranular Creep Resistance of IN740H and It's Variant
||CheolHyeok Yang, DongMin Kim, ChiWon Kim, HiWon Jeong, HyunUk Hong
|On-Site Speaker (Planned)
In this study, three heat treatments were designed based on thermodynamic analysis of Inconel 740H, considered material for A-USC steam turbines. After long-term thermal exposure(750 ℃) for 5,000h, the stability of microstructure and mechanical properties was confirmed, and factor that optimize creep properties were derived through the creep test(750 ℃/270MPa). It was confirmed that the content of Cr was concentrated at the MC carbide interface. The MC carbide has increased creep properties because temperature and stress during creep contribute to the Decomposition(MC + γ →M23C6 + γ') for phase transformation. In the case of superalloy developed within the component range of Inconel 740H, the difference in phase transformation was confirmed through thermodynamic analysis. After heat treatment, the grain boundary microstructure was also different. This difference led to a result that continuous distribution and blocky type of carbide induced optimizing the grain boundary deformation by dislocation gliding after the creep(750 ℃/270MPa).