【摘要】 在一种高性能无Re镍基单晶高温合金中分别添加一定质量分数的Ru和Cr,通过DTA,OM,SEM和EPMA等分析方法,研究Ru添加以及Cr含量变化对无Re合金凝固特性的影响.结果表明,Ru添加会增加共晶面积分数,使铸态组织中析出富Ru相,富Ru相析出量随Ru和Cr的同时添加而大量增加;Ru添加能促进TCP相形成元素W向枝晶干偏聚,抑制Mo向枝晶间偏聚;Cr含量增加能降低W的偏析系数,但对Mo的偏析系数无明显影响;Ru和Cr会共同作用影响合金的凝固组织及偏析,从而影响合金热处理工艺的制定和合金的组织稳定性.更多还原

【Abstract】 The effect of addition of Ru and change of Cr content on solidification behaviors are systematically investigated in a Re-free Ni-based single crystal superalloy with a fixed mass fraction additions of Ru and Cr,with the use of DTA,OM,SEM and EPMA.The results show that the addition of Ru can increase the eutectic fraction,facilitate the formation of Ru-rich phase which would increase largely at the time of Ru and Cr addition synchronously.Ru addition can promotes W segregate to the dendrite arm,and inhibits Mo to segregate to the interdendritic region.The increasement of Cr addition can decrease the segregation ratio of W,but have little effect on Mo.The combination of Ru and Cr influences the solidification microstructures and segregation behaviors corporately,and thus influences heat treatment processes and the microstructure stability.更多还原