关键元素对Co-30Ni-4Al-3W合金组织性能影响的热力学解析

Thermodynamic Analysis of the Effect of Key Elements on the Microstructure and Properties of Co-30Ni-4Al-3W Alloy

采用热力学方法分析了Ti、Mo和Cr对低W含量Co-30Ni-4Al-3W合金的析出相类型、γ′相溶解温度和析出量、屈服强度及密度的影响。结果表明,Ti、Mo和Cr均提高了γ′相溶解温度和析出量,其中Ti的作用最为显著;Ti和Cr降低室温密度,Mo对密度的影响较小;Ti增加室温和高温屈服强度,Mo和Cr对屈服强度的影响较小;三种元素适宜的添加量分别为2%~4%、小于2%和5%~7%。根据元素影响规律,设计了一种名义成分为Co-30Ni-4Al-3W-3Ti-7Cr的新型Co基合金,其室温和高温强度比Co-30Ni-4Al-3W合金显著提升。

The influence of Ti,Mo and Cr on the Co-30Cr-4Al alloy with low W content were investigated by thermodynamic analysis in terms of precipitate types,the dissolution temperature and compositions ofγ′phase,yield strength at room and high temperatures and density.The results show that Ti,Mo and Cr increase the dissolution temperature and phase fraction ofγ′phase.Ti and Cr reduce the density,while Mo has little influence on density.Ti increases the yield strength at both room temperature and high temperatures.And the influence of Mo and Cr on the yield strength are minor compared with Ti.The recommended addition of Ti,Mo and Cr is 2%—4%,less than 2%and 5%-7%,respectively.A new type Co-based alloy with the nominal composition of Co-30Ni-4Al-3W-3Ti-7Cr is designed and its yield strengths in the whole temperature range are higher than that of Co-30Ni-4Al-3W alloy.