1.School of Mechanical Engineering,Dalian Fisheries Univ., Dalian 116023,China; 2.Department of Material Engineering,Dalian University of Technology,Dalian 116024,China
Abstract: Three alloys of Cast, FC and WQ heat-treated TiAl-12Nb-2.5Cr with different phase compositions and microstructures were prepared. Interrupted oxidation behaviors of these alloys at 1 000℃ in static air were studied using oxidation mass gain analysis. The structure and components of the oxide scales were analyzed by XRD and EPMA. The results indicate that alloy elements enhance oxidation resistance of the alloy, but adding high content of Nb and Cr results in the metastable β phase in the room-temperature structure. The existence of β phase makes the adhesion of the oxide worse, accelerating the spallation of the oxide. The FC alloy with main phase of γ+α_2 will have a protective oxide scale after eliminating β phase in the alloy by heat treatment.
2004, Vol. 19 
