熔炼时间对稀土单晶合金坩埚界面反应的影响

为了实现稀土单晶高温合金中稀土含量的稳定控制，明确稀土元素在熔炼过程中参与的坩埚界面反应机理，研究了熔炼时间对含Y高温合金CMSX-4与Al2O3陶瓷坩埚在真空感应熔炼过程中的界面反应和稀土Y收得率的影响。实验结果表明：随着熔炼时间的延长界面反应加剧，熔炼过程中Y首先与Al2O3陶瓷基体发生反应生成Y2O3，生成的Y2O3会继续与Al2O3发生反应生成Y、Al原子比不同的铝酸钇反应层，最终坩埚表面形成的界面反应产物由外层的YAlO3、内层的Y3Al5O12(Y3Al2(AlO4)3) 以及附着的高温合金组成。熔炼10~30min时合金中稀土Y收得量为41.023、4.566和5.368ppm。

Effect of Melting Time on Crucible Interfacial Reaction of Rare Earth Single Crystal Alloy

In order to realize the stable control of rare earth content in rare earth single crystal superalloy and clarify the crucible interface reaction mechanism that rare earth elements participate in the melting process, the effect of melting time on the interfacial reaction of Y-containing superalloy CMSX-4 and Al2O3 ceramic crucible during vacuum induction melting and the residual amount of rare earth Y were studied. The results show that with the extension of melting time, the interfacial reaction becomes more severe. During the melting process, yttrium first reacts with the Al2O3 matrix to form Y2O3, and Y2O3 will continue to react with Al2O3 to form yttrium aluminate reaction layer with different atomic ratios of Y and Al. The final interface reaction product formed on the crucible surface is composed of YAlO3 in the outer layer, Y3Al5O12 (Y3Al2(AlO4)3) in the inner layer and the attached superalloy. The residual amount of rare earth Y in the alloy was 41.023, 4.566 and 5.368 ppm when melting for 10~30 min.