【摘要】 利用Thermal-calc热力学软件对GY200平衡条件下的析出相进行了计算,并结合金相、扫描、化学相分析等手段研究了700、750℃不同时效时间下先进超超临界电站叶片用GY200镍基合金的组织、性能、碳化物及沉淀强化相的演变。结果表明,GY200镍基合金在700、750℃时效后的强度明显增加,冲击性能稍有下降,在10 000 h时效时间内合金的各项性能没有明显变化。长时时效后的碳化物主要由M₂₃C₆和MC相组成,和热力学软件模拟结果一致,利用2%的W替代Waspaloy中1%的Mo,合金中没有M₆C析出。随着时效时间增加M23C6相含量增加,并呈链状和片状析出在晶界,750℃时效M₂₃C₆粗化更加明显;MC相数量在时效3000 h后开始下降。700℃时效3000 h后,γ′相数量开始增加,5000～10 000 h趋于稳定,750℃时效γ′相数量基本不变。γ′相在700℃时效稳定性较好,粗化速率较低;750℃时效γ′相粗化速率较高,5000 h时效后γ′相平均尺寸约100 nm。更多还原

【Abstract】 The precipitates in GY200 equilibrium conditions were calculated by thermal-calc thermodynamic software. The microstructure,performance, carbides and γ’ phase evolution of GY200 nickel base alloy for the blades of an advanced super supercritical power station at700 and 750 °C with different aging time were studied by metallography, scanning, and chemical phase analysis. The results show that the strength increases significantly after aging, and the impact performance decreases slightly. The carbides mainly consist of M₂₃C₆ and MC phases. M₆C can not precipitate from matrix when replacing of 1% Mo in Waspaloy by 2% W. The content of M₂₃C₆ phase increases with the increase of aging time, and the carbides separate out as chains and lamellae in the grain boundary. The amount of MC phase begins to decrease after aging for 3000 h. The amount of γ’ phase increases after aging at 700 °C for 3000 h, stabilizes after 5000 h, and remains basically unchanged at 750 °C. The γ′ phase has good thermal stability at 700 °C with a low coarsening rate. The coarsening rate at 750 °C is higher and the diameter of γ′ is about 100 nm after aging for 5000 h.更多还原