An aluminide（AlFe and α-（FeAl）） surface layer containing lower-Al was formed on ferritic-martensitic steel P92 by means of surface mechanical attrition treatment（SMAT） combined with a duplex aluminization proce...An aluminide（AlFe and α-（FeAl）） surface layer containing lower-Al was formed on ferritic-martensitic steel P92 by means of surface mechanical attrition treatment（SMAT） combined with a duplex aluminization process at lower temperatures,i.e.a packed aluminization followed by a diffusion annealing treatment below its tempering temperature.Indentation tests indicated that the lower-Al surface layer formed on the SMAT sample is more resistant to cracking and has better adhesion to the substrate in comparison with the Al 5Fe 2 layer formed on the as-received sample after the duplex aluminization process.Isothermal steam oxidation measurements showed that the oxidation resistance is increased significantly by the lower-Al surface layer due to the formation of a protective（Fe,Cr）Al 2O 4 layer.The rate constant of oxidation was estimated to decrease from-0.849 mg^2 cm^-4h^-1 of the as-received material to^0.011 mg^2 cm^-4 h^-1 of the AlFe layer at 700 ℃.展开更多
基金Financial supports from the Ministry of Science and Technology of the People’s Republic of China (No.2012CB932201)the National Natural Science Foundation of China (No.91226204)the Key Research Program of Chinese Academy of Sciences (No.KGZD-EW-T06)
文摘An aluminide（AlFe and α-（FeAl）） surface layer containing lower-Al was formed on ferritic-martensitic steel P92 by means of surface mechanical attrition treatment（SMAT） combined with a duplex aluminization process at lower temperatures,i.e.a packed aluminization followed by a diffusion annealing treatment below its tempering temperature.Indentation tests indicated that the lower-Al surface layer formed on the SMAT sample is more resistant to cracking and has better adhesion to the substrate in comparison with the Al 5Fe 2 layer formed on the as-received sample after the duplex aluminization process.Isothermal steam oxidation measurements showed that the oxidation resistance is increased significantly by the lower-Al surface layer due to the formation of a protective（Fe,Cr）Al 2O 4 layer.The rate constant of oxidation was estimated to decrease from-0.849 mg^2 cm^-4h^-1 of the as-received material to^0.011 mg^2 cm^-4 h^-1 of the AlFe layer at 700 ℃.
