| Summary: | The objective of this study is to investigate
the oxidation behavior of binary ?-TiAl based
intermetallic; with composition (at%) of 45A, 48Al and
50Al, and ternary alloys of Ti-48Al containing 2Cr and
4Cr. Thermal cyclic oxidation was conducted
discontinuously at temperatures of 7000C and 9000C in
static laboratory air. Optical microscopy, Scanning
Electron Microscopy (FESEM), Energy Dispersive Xray
Analysis (EDX) and X-ray diffraction (XRD)
techniques were employed for the analysis. SEM
examination of cross-sectional samples using secondary
electron and line-scan analysis after exposure at 7000C
showed that non-adherent oxides scales formed due to
the spallation caused by cyclic condition. While,
exposure at 9000C, only binary alloys exhibited
breakaway oxidation while the oxides scale formed on
the ternary alloys were well-adhered on the substrate
alloy. Overall, exposure at 9000C resulted in thicker and
harder oxide scales and addition of Cr believed to
improve oxidation resistance of Ti-Al based
intermetallics at higher temperature
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