机械合金化Fe-20Cr-2.5Al合金循环氧化行为

Cyclic Oxidation Behavior of Mechanical Alloying Fe-20Cr-2.5Al Alloy

采用机械合金化及热压法制备Fe-20Cr-2.5Al、Fe-20Cr-2.5Al-0.8Y2O3和Fe-20Cr-2.5Al-3Y2O3合金,研究了不同Y2O3含量对MA Fe-Cr-Al合金在900℃空气中循环氧化行为的影响。结果表明,Fe-20Cr-2.5Al合金氧化增重最大,Fe-20Cr-2.5Al-3Y2O3合金氧化增重其次,Fe-20Cr-2.5Al-0.8Y2O3合金氧化增重最少,抗高温循环氧化性能最好。Fe-20Cr-2.5Al合金的氧化膜分为三层,外层主要为Fe2O3,与镍层连接界面有很薄一层不连续的Al2O3,中间层主要为Fe2O3和Cr2O3的复合氧化物,氧化膜内层主要为Fe Cr2O4;Fe-20Cr-2.5Al-0.8Y2O3合金的氧化膜没有明显分层现象,氧化膜主要为Cr2O3;Fe-20Cr-2.5Al-3Y2O3合金的氧化膜分为两层,外层主要由Al2O3和Cr2O3交替连接形成,内层主要由Cr2O3组成,有很薄的复合氧化物Fe Cr2O4。Y2O3的添加可有效提高Fe-20Cr-2.5Al合金的抗循环氧化能力,其中Fe-20Cr-2.5Al-0.8Y2O3合金好于Fe-20Cr-2.5Al-3Y2O3合金。

Fe-20Cr-2. 5Al,Fe-20Cr-2. 5Al-0. 8Y2O3 and Fe-20Cr-2. 5Al-3Y2O3 alloys were prepared by mechanical alloying and hot pressing. The effects of different Y2O3 content on cyclic oxidation behavior of mechanical alloying Fe-20Cr-2. 5Al alloy at 900 ℃ in air were investigated. The results indicate that the oxidation weight-increment of Fe-20Cr-2. 5Al alloy becomes the highest and then Fe-20Cr-2. 5Al-3Y2O3 alloy,Fe-20Cr-2. 5Al-0. 8Y2O3 alloy. The oxide scales of Fe-20Cr-2. 5Al alloy were divided into three layers. The outside layer was mainly Fe2O3,and there was a discontinuous layer of Al2O3 between the outside layer and the nickel plating layer. The intermediate layer was composed of composite oxide of Fe2O3 and Cr2O3. The inside layer was mainly Fe Cr2O4. The oxide scales of Fe-20Cr-2. 5Al-0. 8Y2O3 had no conspicuous layering,and were mainly Cr2O3. The oxide scales of Fe-20Cr-2. 5Al-3Y2O3 alloy were composed of two layers,the outside layer of Al2O3 and Cr2O3,the inside layer with Cr2O3 and small amount of Fe Cr2O4. Y2O3 can improve the cyclic oxidation resistance of Fe-20Cr-2. 5Al alloy effectively,and the cyclic oxidation resistance of Fe-20Cr-2. 5Al-0. 8Y2O3 alloy is slightly better than Fe-20Cr-2. 5Al-3Y2O3alloy＇s.