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研究了Alloy 617 mod在750℃下时效3 000 h过程的析出相种类及其对室温硬度和冲击性能的影响。Alloy 617mod时效后析出M23C6碳化物和?’相。随时效时间延长,晶内、晶界析出物数量增多,晶界碳化物尺寸和分布无明显变化。经300 h时效后,M23C6和?’相产生析出强化,提高了合金硬度。晶界碳化物导致界面结合强度降低,晶界成为裂纹的发源地,引起冲击吸收能量降低。时效过程?’相与基体相保持共格关系,产生共格应力,有利于硬度提高;同时?’相析出强化使晶界附近难以协调塑性变形,易导致开裂,也引起冲击吸收能量降低。时效300~3 000 h过程的时效态Alloy 617 mod硬度和冲击吸收能量分别为207~214 HB和75~83 J,具有良好的稳定性。
The species of precipitated phase of Alloy 617 mod after aging at 750 ℃ for 3 000 h and its effect on the room temperature hardness and impact properties were studied. Alloy 617mod after precipitation aging M23C6 carbide and? ’Phase. With the extension of aging time, the amount of precipitates increased in the grain boundaries and grain boundaries, and there was no obvious change in the size and distribution of the grain boundaries. After 300 h aging, M23C6 and? ’Phase precipitation hardening, increased alloy hardness. The grain boundary carbides lead to the decrease of the bonding strength of the interface, and the grain boundary becomes the cradle of the crack, causing the impact absorption energy to decrease. Aging process ’phase and the matrix phase to maintain a coherent relationship, resulting in a coherent stress, is conducive to increase the hardness; while the’ phase precipitation hardening difficult to coordinate near the grain boundary plastic deformation, easily lead to cracking, but also reduce the impact of absorption energy. The aging and impact energy absorption of Alloy 617 mod aged from 300 to 3000 h were 207 ~ 214 HB and 75 ~ 83 J, respectively, which showed good stability.