Inhibition of interface reaction of DZ22B alloy and high purity Al 2 O 3 mould surface by changing directional solidification process parameters

Abstract

The effect of casting temperature and withdrawal rate on the interfacial reaction between DZ22B nickel-base superalloy and high-purity Al2O3 ceramic shell facecoat material was studied by changing the parameters of directional solidification process.The SLM was used to observe the different characteristic regions of the macroscopic reaction. The SEM analysis equipped with EDS was used to study the microstructure of the alloy-formed shell interface and the qualitative analysis of the interfacial reaction product elements. The phase and element valence of the interfacial reaction product were identified by XRD and XPS.The results show that the interface reaction products are mainly HfO2 and Al1.98Cr0.02O3 and exhibit a sub-regional distribution along the direction of directional solidification.Under the premise of ensuring the directionally solidified alloy structure, lowering the pouring temperature and increasing the withdrawal rate can inhibit the occurrence of delayed interface reaction.