| The γ-TiAl based alloy has specialties of low density,high specific strength and elasticmodulus,and good high temperature strength and so on,So it is considered to be one of the promisinghigh temperature strucyural materials, and it has great benefit in the development of aeronautics andastronautics, the advanced automotive and steam turbine. However, the key issues need to be resolvedis that the low wear resistance and the poor high-tenperature oxidation resistance restrict its practialapplication.To solve these problems，surface treatment techniques are effective ways to improve tribologicalproperties γ-TiAl alloy and high-temperature oxidation resistance. In this paper, the NiCr alloyinglayer and NiCr-O composite alloying layer were prepared on γ-TiAl alloy by using the double glowplasma alloying technique. The microstructure, composition and phase structure of the surfacemodified layers will be analyzed by means of Optical microscopy (OM),energy dispersivespectrometer（EDS）,X-ray diffraction(XRD) and phase electron microscopy（SEM）,respectively,theelastic modoulus of alloying layers,the micro-hardness, wear resistance at room temperature and hightemperatue(500℃),and high temperature oxidation resitance at different temperature.The result shows that: In the optimum process parameters, the better modified layers can beacquired. The compositin of surface modified layer distributed gradually from surface to substrat ofthe γ-TiAl substrate and formed metallurgical bonding between alloyed layers and substrate. NiCralloying layer and NiCr-O composite alloying layer are proved to benefical to the wear resistance ofthe γ-TiAl at both room temperatrue and high temperature (500℃) and high-temperature oxidationresistance of the γ-TiAl base alloy. Especially the high-temperature oxidation resitance of NiCr-Ocomposite alloying layer has a greater increase from the γ-TiAl base alloy. |
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