Wear resistance of Zr-N alloyed layer on TC4 alloy surface at room temperature and 600°C

Zr-N alloyed layers were fabricated on the surface of Ti6Al4V alloy by two kinds of surface alloying processes to improve the wear resistance of Ti alloy at the room and elevated temperature. One process is Zr-diffusing with nitriding simultaneously (Zr+N), and the other is nitriding after Zr-diffusing (Zr/N). The tribological property of two kinds of modified surface layers at room temperature and 600°C were investigated with ball-disk tester. The results show that both the Zr-N diffusion layers consist of ZrN phase, and Zr/N layer also contains a small amount of TiN phase and thicker Zr-Ti solid solution. The surface hardness of the tested alloy is significantly increased by both Zr-N alloying layers. The hardness, thickness and surface bearing capacity of Zr/N layer are greater than those of Zr+N layer. Under room temperature and 600°C, the wear rate of Zr/N layer is reduced by 43 and 21 times than matrix respectively, and the wear rate of Zr+N layer is reduced by 24 and 5 times than matrix respectively.