Microstructure and oxidation resistance of spark plasma sintered Yttria-Zirconia ODS steels

摘要

In this experiment, the effect of Y2O3 and ZrO2 additions on the microstructure and cyclic oxidation resistance of 17-Cr ODS steel containing Al consolidated using spark plasma sintering method were studied. In addition, density, porosity and hardness were also observed. Four compositions of ferritic steels as Fe-17Cr-3.5Al-Ti-Y ('FP'),Fe-17Cr-3.5Al-Ti-Y-0.4Y2O3 ('FY'), Fe-17Cr-3.5Al-Ti-Y-0.4ZrO2 ('FZ'), and Fe-17Cr-3.5Al-Ti-Y-0.2Y2O3-0.2ZrO2 ('FYZ') were prepared by mechanical alloying and followed by sintering at 1000 °C. Microstructure characteristics were observed for different aspect, viz. elemental distribution, composition, and phase identification. Cyclic oxidation tests were carried out at 800 °C for 8 cycles. The results show that ZrO2 addition suppresses the formation of Y-Al-O clustering and promotes the formation of Y-Zr-O clustering and the enhancement of oxidation resistance of the alloy. However, in some condition it also has a deleterious effect on crack resistance. In contrast, the addition of Y2O3 decreases the oxidation resistance but increases the hardness.