Study On The Design And Friction-reducing Properties Of The Hybrid Micro-structure Of Tool Surface

As an effective and easy way to reduce friction,surface microstructures are applied to the surface of engine cylinder,bearing and cutting tool to reduce wear.Titanium alloy is a difficult machining material,and the tool wear is especially serious.The introduction of hybrid microstructure to tool surface will change the contact state of tool-chip interface and reduce tool wear.The effects of surface hybrid microstructure on the friction reducing performance of TC4 titanium alloy by YG8 cutting tools are researched.The main contents are as follows:(1)FLUENT is used to simulate the distribution and loading of lubricant between tool-chip interface.Different density,depth and shape of microstructures,as well as different lubricating film parameters,were set to obtain different lubricating conditions.These parameters are optimized to make tool-chip interface in the best state of lubrication.The change in the arrangement and shape of microstructure can affect pressure distribution,bearing capacity and inlet mass flow rate of the lubricant.The variable density hybrid microstructure,variable shape hybrid microstructure and variable shape and density hybrid microstructures have been optimized and designed.(2)The influence of laser processing parameters,such as energy density,scanning speed and defocus,on the size and morphology of the microstructure of YG8 cutting tool was studied.By selecting suitable parameters of laser,single microstructure,variable density hybrid microstructure,variable shape hybrid microstructure,and variable shape and density hybrid microstructure were fabricated,whose parameters and arrangement conform to the results of simulation.(3)The experiment of cutting TC4 titanium alloy by YG8 cutting tools was carried out under both dry cutting and minimum quantity lubrication(MQL)conditions.The effects of cutting tools with non-microstructure,single microstructure,variable density hybrid microstructure,variable shape hybrid microstructure and variable shape and density hybrid microstructures on cutting force and average friction coefficient of rake face are studied,respectively.Meanwhile,the wear of these 5 kinds of tools was compared.The microstructure which has the best antifriction effect is optimized,and the friction reduction mechanism of surface hybrid microstructure on the tool is analyzed.