Design,Fabrication And Cutting Performance In Machining Titanium Alloys Of Micro-Textured Tools

Titanium alloys are widely used in the aerospace and aeronautics because of their excellent mechanical properties.However,the high temperature,high pressure and a large number of bonding phenomena on the tool's surface during the processing lead to serious tool wear and have negative effect on tool's life.In order to change the friction environment between the tool and the chip,reduce the vibration in the friction interface,and extend the service life of the tool,three kinds of groove texture were machined on the surface of the cemented carbide tools,and the antifriction mechanism and the cutting performance in machining titanium alloys of the micro-textured tools were investigated.The main research contents are as follows:(1)Preparation of the laser texture on cemented carbide surface.Three critical factors,laser power,scanning speed,scanning times,were selected to study the effect on size and morphology of texture.Then found the optimal parameters.Laser processing parameters with laser power of 40 W,scanning speed of 100 mm/s and scanning times of 200 times were selected.Line,sinusoidal and rhombic groove textures were machined on the rake face of cemented carbide tools.(2)Analysis of friction reduction mechanism of micro-textures on cemented carbide surface under dry friction.A three-dimensional model of micro-textured cemented carbide and titanium alloy simulation model under dry friction was established by finite element software ABAQUS.The variations of stress and temperature of cemented carbide and titanium alloy during friction were analyzed by the simulation.In order to compare the performance of the existence of micro-texture on the surface of cemented carbide,the friction and wear experiments of non-textured cemented carbide sample and three kinds of textured cemented carbide sample with different sliding speeds and loads were carried out.The friction coefficient of different kinds of micro-textured cemented carbide samples under different sliding conditions was studied.The analysis,surface wear morphology of cemented carbide samples and titanium alloy samples and the surface bonding phenomenon and surface element composition,provided basic instruction and reference for the follow-up study of friction reduction and wear reduction mechanism.(3)Analysis of friction reduction mechanism of micro-textures on cemented carbide surface under lubrication condition.Three-dimensional simulation model of lubricant and its distribution on the surface of micro-textured cemented carbide was established by FLUENT,and the film pressure variation law of lubricant between the interface of micro-textured cemented carbide and titanium alloy during friction was analyzed.By studying the load-carrying capacity of lubricating film,the performance of different kinds of groove texture in improving the friction characteristics of contact surface under hydrodynamic lubrication was evaluated.At the same time,the friction and wear experiments of different kinds of cemented carbide sample lubricated by cutting fluid under different friction conditions were carried out,which were used to analyze the influence of the kinds of texture of material surface on the hydrodynamic lubrication performance of cemented carbide surface under lubrication condition and its mechanism.(4)Investigation of the cutting performance of micro-textured tools in machining titanium alloys under dry cutting and cutting fluid lubrication.Four kinds of cutting tool,non-textured tool,line textured tool,sinusoidal textured tool and rhombic textured tool,were tested in machining titanium alloys with different cutting parameters.The cutting force,friction coefficient between tool and chip interface,chip morphology,wear of tool's rake face and flank face and surface quality of workpiece were analyzed systematically.The mechanism of tool's wear and the state of bonding layer were studied,and the mechanism of micro-texture for reducing tool wear and improving tool life was revealed.In this study,three kinds of groove texture were designed and fabricated on the surface of cemented carbide.By combining numerical simulation with experimental investigation,the anti-wear and friction-reducing properties of the micro-texture on the tool's rake face were systematically analyzed.The project research is of great significance for improving the surface quality of titanium alloy,reducing tool wear rate and prolonging tool life.