(北京航空航天大學 材料科學與工程系， 北京 100083)
摘 要: 利用元素氮和元素碳對 γ TiAl合金(簡稱TiAl合金)進行激光表面合金化處理，分別制得了以TiN及TiC硬質(zhì)耐磨相為增強相的快速凝固原位耐磨復合材料表面改性層，改性層與基體間為完全的冶金結合，其顯微組織從熔池底部到自由表面具有梯度漸變特征，越接近自由表面，增強相越密集。較系統(tǒng)地研究了激光表面合金化工藝參數(shù)對改性層顯微組織以及在磨料磨損及滑動磨損條件下耐磨性能的影響。激光束掃描速度越低，表面改性層增強相體積分數(shù)越高，材料顯微硬度提高越多，耐磨性越強。
關鍵字: γ TiAl合金； 激光表面合金化；耐磨性
（Department of Materials Science and Engineering，Beijing University of Aeronautics and Astronautics，Beijing 100083， P.R.China）
Abstract:Laser surface alloying with nitrogen and carbon were employed to produce modified layers on TiAl alloy. The rapidly solidified insitu composites layers reinforced by titanium nitride and titanium carbide were gained respectively, and the interfaces between the layers and substrate were metallurgic bonds. From bottom of molten bath to free surface, there was gradient change characteristic in microstructures. The nearer the free surface, the higher the volume fraction of reinforced phase. The effects of laser processing parameters on microstructures and wear resistance of surface alloyed layer were studied. With decreasing laser beam scanning rate, the volume fraction of reinforced phase increases, the microhardness of the samples increases and the wear resistance is improved.
Key words: γ TiAl intermetallics; laser surface alloying; wear resistance
