High Temperature Oxidation And Wear Behavior Of Fe-Cr-Al Alloy

In this paper,Fe-Cr-Al alloy was selected as the research object.The isothermal oxidation experiments of Fe-21.3Cr-3.5Al alloy at 1220-1340?for 3 h and the continuous oxidation experiments at 1280?were carried out.The effects of C and Al on the high temperature oxidation of Fe-Cr-Al alloy were also discussed.The effects of oxidation temperature,oxidation time and element composition on the morphology,depth,hardness and wear properties of Fe-Cr-Al alloy oxide film were studied by SEM,XRD and EDS.the high temperature oxidation process and mechanism were explored.The results show that with the increase of oxidation temperature,the oxidation weight of Fe-21.3Cr-3.5Al alloy increases step by step.The oxidation layer is mainly composed of Al₂O₃and a small amount of Zr O₂and Fe₂O₃.Zr O₂increases continuously in the range of 1220-1340?,and the content of Al₂O₃first increases and then decreases on the surface.The content of Al₂O₃reaches the maximum at1260?.With the increase of temperature,the content of Al₂O₃decreases and the content of Fe₂O₃begins to increase.Fe-21.3Cr-3.5Al alloy has good oxidation resistance below 1280?and unstable oxidation resistance above 1300?.As for the thickness of the oxide layer,the oxide layer is the most uniform at 1260?,the oxide film is thicker and more uniform at 1280?,and the oxide film gradually becomes inhomogeneous at temperatures above 1300?.With the increase of oxidation temperature,the hardness of oxide layer increases.The wear mechanism of Fe-21.3Cr-3.5Al alloy is abrasive wear and oxide film spalling.With the increase of oxidation temperature,the wear resistance of the oxide layer increases,and the wear rate is the lowest at 1280?.When the oxidation temperature rises to 1320?,the oxide film peels off.The results show that the properties of Fe-21.3Cr-3.5Al alloy are similar to that of KCF.When Fe-21.3Cr-3.5Al alloy is oxidized at 1280?for 1-5h,the oxidation kinetics curve follows the law of power function.At the beginning of oxidation,the content of alumina increased significantly,and the content of alumina remained stable after 3 h.With the increase of oxidation time,the thickness and hardness of oxide layer increase.The effects of C and Al on Fe-Cr-Al alloy were studied by designing Fe-Cr-Al alloy with different elements.The range of C and Al was 0.0068%-0.036%and 2.4%-3.2%,respectively.The results of isothermal oxidation at 1260?and 1280?for 3h show that the oxidation resistance of Fe-Cr-Al alloy decreases with the increase of C,and increases with the increase of al.With the increase of C content,the spalling phenomenon after oxidation becomes more and more obvious,and the oxidation weight gain is also increasing.At 1260?and 1280?for 3 h,when the C content is0.0068%,the surface of oxide film is mainly alumina.When the content of C is0.022%,the surface of oxide film is mainly iron oxide.When the content of C is0.036%,the surface of oxide film is mainly chromium oxide at 1260?,and the surface of oxide film is mainly iron oxide at 1280?.Through the analysis of oxide layer,with the increase of C content,the thickness of oxide layer increases and the hardness of oxide film decreases.Through the analysis of oxide layer,with the increase of Al content,it can promote the formation of more alumina in Fe-Cr-Al alloy,greatly improve the oxidation resistance of the alloy,the thickness of oxide layer decreases gradually,and the hardness of oxide layer increases gradually.