Low-temperature Fabrication And Cutting Performance Of Nano-Al₂O₃ Coated Micro-textured Tools Based On ALD

With the development of cutting processing technology and dry cutting being more and more widely used,the requirements on various aspects of tool performance are getting higher and higher.The main forms of tool failure during dry cutting are severe bonding and severe tool-chip friction,which will cause tool wear and seriously affect the quality of the workpiece and processing efficiency.Therefore,how to effectively reduce the friction between the tool-chip interface,reduce tool adhesion and wear,and prolong tool life is of necessary significance.Studies have shown that the preparation of micro-textured or deposited coatings on the surface of the tool can improve friction and wear resistance,effectively reduce the friction coefficient,and improve the cutting performance of the tool.Combining the two has a synergistic effect.In addition,nano-scale materials have a lower coefficient of friction due to their nano-effects.The combination of nano-coatings and micro-texture is expected to further improve the cutting performance of cutting tools.At present,its effect on the mechanism o f dry cutting is still unclear.Therefore,this article uses atomic layer deposition(ALD)to prepare nano-Al₂O₃ coating micro-texture tool at low temperature.Combining the learned metal cutting principles,modern processing technology and theoretical mechanics.We start from exploring the influence of the combination of microtexture and nano-Al₂O₃coating on the dry cutting process mechanism of the tool.Carry out research work on the design and preparation of tool,performance characterization,cutting performance and chip formation mechanism,etc.With a view to providing an experimental basis for related research and improving the cutting performance of the tool.The following is a brief introduction to the main research content of this article:(1)Nano-Al₂O₃ coating micro-texture tool were prepared at low temperature based on ALD technology,and the effect of nano-Al₂O₃ coating on tool performance was studied.Using the MF-20-E laser coding machine,the micro-textures were machined on the rake face of the YT5 cemented carbide tool.Then,the ALD technology was used to deposit Al₂O₃coatings with thicknesses of 50nm,100nm and 200nm on the tool surface to prepare micro-textur tool,nano-Al₂O₃ coating tool and nano-Al₂O₃ coating micro-texture tool.The tool morphology and mechanical properties were characterized.The accuracy of the micro-texture and coating size was tested.The adhesion of the coating to the YT5 tool substrate was tested.The effect of the coating on the mechanical properties of YT5 tool material was studied.The results showed that the nano-Al₂O₃ coating prepared by ALD method had little effect on the mechanical properties of the tool material.(2)The cutting performance of nano-Al₂O₃ coating micro-texture tool was studied and compared with YT5 tool and micro-texture tool.The effects of micro-texture morphology and size parameters and coating thickness parameters on the three-dimensional cutting force of the tool,the average friction coefficient between the tool and the chip,and the rake face morphology were analyzed.It was found that the micro-texture can improve the cutting performance of the tool.The coating can further improve the cutting performance of micro-textured tools,of which the cutting performance of 100nm Al₂O₃ coating micro-texture tool is better.When the dot-like micro-texture spacing is 0.15mm,the cutting performance is optimal.The effect of improving the cutting performance is most obvious when the strip microtexture direction is perpendicular to the main cutting edge.The cutting performance of the tool will change to some extent with the change of cutting speed.(3)The effects of micro-texture and nano-Al₂O₃ coating on chip morphology were studied,and the chip formation mechanism was also discussed.The difference between the macroscopic and microscopic morphology of the chips produced by the tool is analyzed.The results show that micro-texture can collect debris,promote chip breaking and chip removal,reduce adhesion,reduce furrow effect.The micro-texture and coating reduce the actual contact length between the tool-chip interface and coordinately change the friction between the tool-chip interface from sliding friction to sliding-rolling composite friction.It is beneficial to reduce friction coefficient,friction force and three-way cutting force,so that tool wear is significantly reduced and tool performance is improved.