Effect of Yttrium Content on the Cast Microstructure of CoNiCrAlY Alloy Ingots and Powders

The CoNiCrAlY alloy ingots and powders with different yttrium content were prepared by vacuum induction melting and vacuum inert gas atomization respectively.The cast microstructure was studied.The result showed that:The extent of yttrium segregation increased as yttrium content became higher.An obvious dendrite texture existed in the cast microstructure,and the amount of dendrite decreased as yttrium content increased.Fish-bone-like dendrite could be found in the microstructure of ingots when the yttrium content reached 1.4%.And it was found that the microstructure of powders was similar to that of ingots.However,yttrium segregation can hardly be found in the microstructure due to the rapid cooling effect of the gas for atomization when the yttrium content in the powder was 0.61%.