借助扫描电镜、透射电镜和力学性能分析研究镍基合金740H 在750°C 时效10000 h 过程中的显微组织和相析出行为及其对室温硬度和冲击性能的影响。供货态镍基合金740H 的硬度低至 HB 168，最高冲击吸收能量为96 J。经800°C 标准热处理16 h 后，晶内析出细小γ'颗粒，晶界析出少量碳化物，硬度提高到 HB 304，冲击吸收能量降至15 J。当合金在750°C 时效300 h 时，硬度达到最大值 HB 331。随着时效时间由300 h 延长至10000 h，硬度和冲击吸收能量均降低，晶界碳化物 M23C6数量明显增多，γ'相尺寸粗化。%The microstructure and phase precipitate behavior and their effects on the room temperature hardness and impact toughness of Inconel 740H aged at 750 °C for 10000 h were investigated by SEM, TEM and mechanical analysis. The as-received alloy shows a low hardness value of HB 168 and a highest toughness value of 96 J. After an aging treatment at 800 °C for 16 h and cooled in air (standard heat-treated condition), fine γ′ phase particles precipitate within the grains and small carbide particles are located at the grain boundaries. The hardness increases to HB 304 and the impact toughness decreases to 15 J after standard heat treatment. A maximum hardness value of HB 331 is achieved for the alloy aged at 750 °C for 300 h. With increasing the aging time from 300 to 10000 h, a decrease of the hardness and toughness is observed along with an enhanced quantity of M23C6 particles and the coarsening of γ′ phase.
展开▼
