Study On The Wear Behavior Of Micro-textured WC-10Ni₃Al Tools In Ti6Al4V Machining

Titanium and titanium alloys are the most promising structural materials for the products of the contemporary spacecraft engineering, aircraft, and medicine because of their high specific strength, wide working temperature ranges, and good corrosion resistance. However, titanium alloys are also known as difficult-to-machine materials. Among the existing tool materials, WC-Co carbides are generally regarded as a suitable tool material commercially available in titanium alloy machining. However, the addition of Co binder deteriorates the hardness and corrosion/oxidation resistance of materials but also decreases the elevated temperature strength. When machining titanium alloys with WC-Co tools, the Co binder is susceptible to diffuse from the tool materials to the titanium alloy through the tool-chip interface. These properties greatly affect the cutting performance of the WC-Co cutting tool in titanium alloy machining, especially at high cutting speed. Therefore, developing new WC-based carbides using new binder component with high hardness, good chemical stability and good wear resistance instead of Co binder is extremely necessary.Recently, newly developed cutting tools with functional micro-textures have promising potentials to improve the machinability of titanimum alloys. The micro-textured cutting tools can reduce the titanimum alloys adhesion on the rake face and lower the cutting temperature. Studies on titanimum alloys cutting using micro-textured cutting tools have been reported. However, the base materials of the micro-textured cutting tools are commonly WC-Co cemented carbides. Recent reports mainly focus on the functioning mechanisms of the micro-textures during titaminum alloys cutting. The disadvantages of the WC-Co cemented carbides restrained the usage of the micro-textured cutting tools in a great extent.In this study, WC-10 wt.%Ni3Al cemented carbides was chosen as the research object in comparing with the commonly used WC-Co cemented carbides. The resistance of adhesion-dissolution-diffusion wear against Ti6Al4 V and abrasion wear against Si3N4 of WC-10Ni3 Al were studied. The machinability of laser surface texturing on WC-10Ni3 Al was also studied. Moreover, the effect of the micro-textures on WC-10Ni3 Al cutting tools during cutting of Ti6Al4 V and the relative mechanisms were studied.As the basis of the analysis of the wear mechanisms of WC-10Ni3 Al cutting tools during Ti6Al4 V cutting, the dissolution-diffusion behavior between WC-10Ni3 Al and Ti6Al4 V was studied. Moreover, the anti-adhesion-dissolution-diffusion wear behavior and anti-abrasion wear behavior of WC-10Ni3 Al was also studied. The results showed that compared with YG8, the chemical affinity between WC-10Ni3 Al and Ti6Al4 V is much lower; therefore, WC-10Ni3 Al has better anti-adhesion-dissolution-diffusion wear property compared with YG8. Moreover, due to the higher micro hadrness of Ni3 Al compared with Co, WC-10Ni3Al(HV 1812) has higher Vicker’s hardness than YG8(HV 1660); therefore, WC-10Ni3 Al has better anti-abrasion wear property compared with YG8.WC-10Ni3 Al and YG8 have different laser energy absorbility, thermal conductivity and specific heat capacity due to the difference of binder components. These differences between WC-10Ni3 Al and YG8 lead to different suitable laser-texturing powers. The most suitable laser-texturing power is lower for WC-10Ni3 Al compared with YG8 via analyzing the micro-textures characteristics under different laser-texturing powers. The micro-textures under the most suitable laser powers for WC-10Ni3 Al is more uniform than those on YG8. Furthermore, due to the lower processing temperature and smaller WC grains growth, the micro-hardness decrease near the micro-textures for WC-10Ni3 Al is smaller than that for YG8. WC-10Ni3 Al has better laser surface textures machinability than YG8. Micro-textured WC-10Ni3 Al with certain micro-texture parameters was fabricated using laser surface texturing method.On the basis of the studies above, tool life and wear mechanisms of smooth surface and micro-textured WC-10Ni3 Al cutting tools during titaminum cutting were studied. Compared with YG8, smooth surface WC-10Ni3 Al cutting tools have longer tool life when cutting titanium, especially at higher cutting speed. The main wear mechanism of the rake face wear for WC-10Ni3 Al and YG8 cutting tools is adhesion-dissolution-diffusion wear. However, the rake face wear for WC-10Ni3 Al is less severe than YG8 due to the lower cutting temperature and the lower chemical affinity between WC-10Ni3 Al and Ti6Al4 V. Cutting fluid can increase the tool life and improve the adhesion conditions to certain extent.Tool life and wear mechanisms of micro-textured WC-10Ni3 Al cutting tools during cutting Ti6Al4 V under different cutting speeds were studied. During the dry cutting process of Ti6Al4 V, micro-textures can improve the friction condition between the chip and the rake face of the cutting tool, which leads to lower cutting temperature and reduction of Ti6Al4 V adhesion on the rake face. When cutting fluid was used, micro-textures can facilitate the penetration of the cutting fluid into the cutting area during cutting process, which further reduced Ti6Al4 V adhesion on the rake face and improved the tool life. Meanwhile, the good wear resistance of WC-10Ni3 Al insured that the micro-textures functioned well during the cutting process.The research results showed that micro-textured WC-10Ni3 Al cutting tools can be an alternative choice for high speed cutting of Ti6Al4 V.