CAJ | 학술논문

开展了GH4698盘件后续热处理对盘件显微组织和蠕变性能影响研究以及GH4698盘件标准热处理下750℃的全阶段蠕变行为研究。试验结果表明：GH4698盘件标准热处理后的显微组织由晶内两种尺寸的球状γ′相和碳化物组成。增加第四段热处理后,显微组织有所变化,晶内小γ′相尺寸有所增加,晶界γ′相贫化区的宽度明显减小,晶界颗粒状碳化物析出更加完善。四段热处理后对GH4698盘件在750℃/382 MPa下的蠕变极限有利。 GH4698合金750℃全蠕变曲线以及俄原型机盘件蠕变性能对比表明,GH4698合金在750℃稳态蠕变阶段较短,盘锻件的显微组织和晶粒度的不均匀会造成蠕变性能较大波动,合理的蠕变性能验收条件应为700℃/412 MPa/100 h下残余应变≤0.2%。
개전료GH4698반건후속열처리대반건현미조직화연변성능영향연구이급GH4698반건표준열처리하750℃적전계단연변행위연구。시험결과표명：GH4698반건표준열처리후적현미조직유정내량충척촌적구상γ′상화탄화물조성。증가제사단열처리후,현미조직유소변화,정내소γ′상척촌유소증가,정계γ′상빈화구적관도명현감소,정계과립상탄화물석출경가완선。사단열처리후대GH4698반건재750℃/382 MPa하적연변겁한유리。 GH4698합금750℃전연변곡선이급아원형궤반건연변성능대비표명,GH4698합금재750℃은태연변계단교단,반단건적현미조직화정립도적불균균회조성연변성능교대파동,합리적연변성능험수조건응위700℃/412 MPa/100 h하잔여응변≤0.2%。
The effect of heat treatment on microstructure and creep properties of GH4698 disc and its all-phase creep behavior after standard heat treatment under 750℃ were studied. The results show that GH4698 plate microstructure after standard heat treatment is composed of globular gamma prime phase and carbides within grains. After the fourth stage heat treatment, the microstructure changed. Small gamma prime phase grew up, gamma prime phase dilution zone width along the grain boundary significantly reduced, and carbide precipitation along the grain boundary granular was more perfect. The fourth stage heat treatment is favorable to the creep limit at 750℃/382 MPa, and the process stability is better. The complete creep curves of GH4698 alloy at 750℃ show that the steady-state creep stage of GH4698 alloy at 750℃ is relatively short. The non-uniformity of microstructure and grain size would cause greater fluctuation of the creep properties. The reasonable acceptance condition for creep properties is σp≤0. 2% at 700℃/412 MPa/100 h.