Ni添加量对Co-Al-W基单晶高温合金凝固特性的影响

The effect of Ni addition on solidification characteristics of Co-Al-W based single crystal superalloy was investigated via experimental, thermodynamical and dynamical analysis. Both Ni-free and adding Ni Co-Al-W based single crystal superalloy has the typical dendritic microstructure, and Ni addition increases the primary dendritic arm spacing of single crystal superalloy. Meanwhile, with increasing Ni content, the microsegregation degrees of Al and W elements increase, the microsegregation degree of Ta element decreases, while Ni addition has little influence on the microsegregation degree of Ti element. Moreover, the interdendritic precipitations of Ni-free single crystal superalloy are primary γ' phase and (β+γ') eutectic phase, while the interdendritic precipitation of Ni single crystal superalloy is primary γ' phase, which indicates that Ni addition changes the solidification path and as-cast microstructure of single crystal superalloy. In addition, the influence of Ni addition on solidification characteristic temperatures of Co-Al-W based single crystal superalloy is not obvious.