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研究了新型镍基GH4586B合金750℃下长期时效1500 h对组织及750℃和510 MPa持久性能的影响。利用扫描电子显微镜观察分析合金长期时效中的显微组织和750℃和510 MPa持久断口变化。结果表明,GH4586B在高温时效中未发现有害TCP相析出,晶界和晶内均析出碳化物,晶界析出碳化物呈弥散的颗粒状,并随时效时间的延长颗粒尺寸有增大的趋势,析出量亦不断增加;合金在750℃和510 MPa下的持久性能主要受晶界碳化物析出的影响,在750℃时效1500 h后750℃和510 MPa持久时间达到最大值,塑性相应最低;通过持久断口的形貌分析,合金750℃和510 MPa持久断裂具有韧性断裂特征。
The effects of long-term aging at 750 ℃ for a new type of nickel-based GH4586B alloy on the microstructure and the permanent properties at 750 ℃ and 510 MPa were studied. The microstructures and long-term fracture changes at 750 ℃ and 510 MPa were observed by scanning electron microscopy. The results show that no precipitated harmful phase of TCP is found in GH4586B during aging, the carbides are precipitated in the grain boundaries and in the grain boundaries, and the carbide precipitates in the grain boundaries are in diffuse granular form. With increasing aging time, the particle size tends to increase, And the amount of precipitates increased. The permanent properties of the alloy at 750 ℃ and 510 MPa were mainly affected by the precipitation of the grain boundary carbides. After 750 ℃ aging at 1500 ℃ for 1500 h, the holding time reached the maximum at 750 ℃ and 510 MPa, and the ductility was lowest. The morphological analysis of the long-term fracture shows that the ductile fracture of the alloy at 750 ℃ and 510 MPa is characterized by ductile fracture.