0Cr15Ni70Ti3AlNb合金平衡析出相热力学计算

Thermodynamic calculation of equilibrium precipitation phases in 0Cr15Ni70Ti3AlNb alloy

采用Thermo-Calc热力学计算软件,模拟计算了0Cr15Ni70Ti3AlNb合金的平衡析出相和凝固过程。结果表明:0Cr15Ni70Ti3AlNb合金的平衡析出相主要包括γ、γ′、MC、M23C6;合金凝固过程中Ti和Nb属于正偏析,Cr、Fe、Si等属于负偏析。Al和Ti是影响0Cr15Ni70Ti3AlNb合金中γ′相析出温度和最大析出含量的主要因素。MC相的析出温度和最大析出含量主要由C元素决定。M23C6相的析出温度主要由Cr元素决定,M23C6相的析出量主要由C元素控制。0Cr15Ni70Ti3AlNb优化合金成分(质量分数)为C(0.03%~0.05%)-Al(0.7%~0.9%)-Ti(2%~2.25%)-Nb(0.75%~0.95%)-Cr(13.5%~15.5%)。研究结果可为合金的成分设计和热处理工艺制定提供理论指导。

Equilibrium precipitation phases and the process of solidification for 0Cr15Ni70Ti3AlNb alloy were studied with the help of thermo-calc software. The main precipitation phases include γ, γ′, MC, M23C6. Positive segregation of Ti, Nb and negative segregation of Cr, Fe, Si may occur during solidification according to the calculation. The contents of Al and Ti have a significant influence on the precipitation temperature and the maximum mass fraction of γ′phase. C is the main control element of the precipitation temperature and the maximum mass fraction of MC. Mass fraction and precipitation temperature of M23C6 are controlled by C and Cr respectively. The optimal composition was found to be C(0.03%-0.05%)-Al(0.7%-0.9%)-Ti(2%-2.25%)-Nb(0.75%-0.95%)-Cr(13.5%-15.5%). Research results can help to understand and instruct composition design and heat treatment process development better.