Y2O3含量对机械合金化Fe-20Cr合金循环氧化行为的影响

摘要

采用机械合金化及热压烧结技术制备Fe-20Cr、Fe-20Cr-0.8 Y2O3和Fe-20Cr-3Y2O3合金,研究Y2O3对Fe-Cr合金在900 ℃空气中循环氧化行为的影响.结果表明:Fe-20Cr合金氧化质量增量最大,Fe-20Cr-0.8Y2O3合金氧化质量增量其次,Fe-20Cr-3Y2O3氧化质量增量最少,抗高温循环氧化性能最好;Fe-20Cr合金氧化100 h后,试样几乎完全被氧化;Fe-20Cr-0.8Y2O3合金的氧化膜分为3层,外层主要为Fe2O3,中间层主要为FeCr2O4,内层主要为Cr2O3;Fe-20Cr-3Y2O3合金的氧化膜也分为3层,外层明显比Fe-20Cr-0.8Y2O3致密,空洞直径比较小,数量也比较少;Y2O3的添加可有效提高 Fe-20Cr 合金的抗循环氧化能力,其中 Fe-20Cr-3Y2O3合金好于Fe-20Cr-0.8Y2O3合金.%Fe-20Cr,Fe-20Cr-0.8Y2O3and Fe-20Cr-3Y2O3alloys were prepared by mechanical alloying and hot pressing.The effects of different Y2O3content on cyclic oxidation behavior of mechanical alloying Fe-20Cr alloy at 900 ℃ in air were investigated.The results indicate that the oxidation weight-increment of Fe-20Cr alloy becomes the highest and then Fe-20Cr-0.8Y2O3alloy,Fe-20Cr-3Y2O3alloy.Fe-20Cr al-loy sample has been almost completely oxidized after 9 h. The oxide scales of Fe-20Cr-0.8Y2O3alloy were divided into three layers,the outside layer was mainly Fe2O3,the intermediate layer was mainly FeCr2O4,and the inner layer was mainly Cr2O3.The oxide scales of Fe-20Cr-3Y2O3alloy similar to Fe-20Cr-0.8Y2O3were divided into three layers,The outside layer was more dense then Fe-20Cr-0.8Y2O3. The diameter of hole is relatively small,the quantity is less.Y2O3can improve the cyclic oxidation resist-ance of Fe-20Cr alloy effectively,and the cyclic oxidation resistance of Fe-20Cr-3Y2O3alloy is slightly better than Fe-20Cr-0.8Y2O3alloy.