Effect of Surface Dendritic Micro Nano Channel Structure Area on Tribological Properties of TiAl Alloy

The dendritic micro nano channels with different structure areas (5.86×10⁵,6.54×10⁵,7.30×10⁵,8.10×10⁵,9.06×10⁵ μm²) were prepared on the TiAl alloy surface by laser marking technique. A solid lubricant composed of mixed powder with Sn poweder, Ag poweder and Cu poweder mass ratio of 90∶5∶5 and graphene powder (mass ratio of mixed powder to praphene was 13∶7) was filled in the channels and then friction and wear tests were carried out. The effect of the dendritic micro nano channel structure area on tribological properties was studied, and the antifriction mechanism was analyzed. The results show that the friction factor and wear rate of the TiAl alloy with different structure areas of dendritic micro nano channel on surface were smaller than those of the TiAl alloy without dendritic micro nano channel. With the increase of the structure area, the wear rate decreased significantly first and then increased. When the structure area was 7.30×10⁵ μm², the average friction factor and wear rate were the smallest, and a complete double-layer lubricating film was formed on the wear surface. Under the structure area of 7.30×10⁵ μm², during friction and wear, the solid lubricant stored in the dendritic micro nano channel and the wear chips generated by the substrate cooperated to repaire the material spalling on the substrate surface caused by fatigue wear, meanwhile the solid lubricant was continuously precipitated from the microstructure to form a complete lubricating film, thus improving the tribological property.