镍基耐蚀825合金的组织特征及热力学计算

Microstructure Characteristics and Thermodynamic Calculation of Incoloy 825

为了了解镍基耐蚀825合金的组织特征及平衡相的析出规律,采用扫描电镜(SEM)和热力学计算软件Thermo-Calc对其进行组织观察和模拟计算分析。结果表明,825合金原始轧态晶界无析出物,晶内有少许Ti的碳化物。750℃时效4h后晶界析出块状M23C6,980℃时效,MC相随时间增加而增多。825合金主要平衡相为γ′、α-Cr、MC、M23C6,Al、Cr、Ti、C分别提高γ′相、α-Cr相、MC相、M23C6相的开始析出温度和最大析出量。

In order to investigate the microstructure characteristics and the precipitation law of equilibrium phases of Incoloy 825,the microstructure was observed by the scanning electron microscopy and the simulation analysis was conducted by Thermo-Calc software.The result indicates that there is not any precipitate at the grain boundary in the original rolling state Incoloy 825 and a few Ti carbides exist within the grains.After aging at 750 °C for 4 h,block M23C6 precipitates at the grain boundary;when aging at 980 °C,MC increases with the time increasing.The main equilibrium precipitated phases of Incoloy 825 include γ′,α-Cr,MC and M23C6.Al,Cr,Ti and C increase the precipitation start temperature and the maximum precipitation amount of γ′,α-Cr,MC and M23C6,respectively.