Stability of Microstructure and Mechanical Properties of GH984G Alloy during Long-term Thermal Exposure
A low cost Ni-Fe-based wrought superalloy for 700 ℃ advance ultra-supercritical coal-fired power plants was developed.The stability of microstructure and mechanical properties of this alloy during long-term thermal exposure was investigated by SEM,TEM and tensile tests.The experimental results showed that the major precipitates in the alloy were spherical γ′,MC and discrete M23C6 distributing along grain boundary after the long-term exposure at 700 and 750 ℃ and no harmful phases,such as σ phase and η phase,were found.However,after exposure at 800 ℃ up to 3000 h,small amount of lath-like η phase precipitated at grain boundary by consuming the surrounding γ′.The η phase exhibited a fixed orientation relationship with the γ matrix.During thermal exposure γ′ coarsened with increasing the exposure time and exposure temperature.In addition,all major phases and their stability temperature ranges were calculated by JMatPro and these results were confirmed by the experimental results.The 700 ℃ tensile tests revealed that the alloy after exposure at 700 and 750 ℃ for 3000 h exhibited excellent ductility and strength.Therefore,the GH984G alloy possessed excellent stability of microstructure and mechanical properties between 700 and 750 ℃ up to 3000 h,and it is a promising material for 700 ℃ advance ultra-supercritical coal-fired power plants.
Ni-Fe-based wrought superalloy:Thermal exposure:Microstructural stability:Precipitate:Mechanical properties
Tingting Wang Changshuai Wang Jianting Guo Lanzhang Zhou
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
国际会议
the Chinese Materials Congress 2012(2012年中国材料大会(CMC2012))
太原
英文
647-653
2012-07-13（万方平台首次上网日期，不代表论文的发表时间）