Basic Experimental Study On Machinability Of Titanium Alloy By Laser Increasing

With the development of aerospace industry,the strength of spacecraft becomes more and more demanding.In the design process,it is necessary to ensure that the structural parts are of light weight,small size,long life and high reliability in complex working environment.Therefore,titanium alloys have been widely used in the field of aeronautics and astronautics.Because of the complex characteristics of structural parts,the traditional material reduction method is of low efficiency and high energy-consumption,thus promoting the development of titanium alloy materials by laser material expansion.Different from conventional casting process,high temperature is produced during laser sintering process,which results in different microstructures of materials,resulting in differences in machinability.In the process of manufacturing,it is necessary to study the machinability of titanium alloy materials made by laser expanding,and draw up the corresponding cutting process.To solve the problem above,aiming at the laser additive manufacturing titanium alloy material,this paper gives some systematic analysis of the quasi static mechanical properties and dynamic mechanical properties of materials,and the following work was carried out based onstudy on the cutting performance:1,Through the quasi-static tensile test,the yield stress of the laser additive manufacturing of titanium alloy materials was studied and the change trend of low strain rate of material flowstress under the condition of internal stress at room temperaturewas analyzed.Through the Hopkinson pressure bar(HPSB)experiment,dynamic mechanical behavior of laser material made of titanium alloy material was analysed andthe trend of material flow stressunderdifferent temperature(30 ℃,150 ℃,300 ℃)and strain rate(3000s-1,5000s-1,8000s-1,10000s-1)was studied,exploring the sensitivity of temperature and strain rate sensitivity of materials.Finally,combining the above tests datas,J-C constitutive model ofthe laser additive manufacturing of titanium alloywas calculatedby linear fitting.2,Through the Third Wave Advantage finite element software,the constitutive model of laser additive manufacturing of titanium alloywas established to run the milling simulation,and theninfluence of machining parameters(spindle speed,feed rate and axial depth of cut)on cutting force and cutting temperaturewas analysedaccording to the simulation results.According tothe method of orthogonal test,a group of milling testwas designed.Finally,the influence of each parameters was analysed and the milling parameters were optimizedbased on the test results.3,Through the Third Wave Advantage finite element software,the constitutive model of laser additive manufacturing of titanium alloywas established to run thedrilling simulation,and theninfluence of machining parameters(spindle speed,feed rate and axial depth of cut)on cutting force and cutting temperaturewas analysed according to the simulation results.According to single test design test method,a group of drilling test was designed.Finally,the influence of each parameters was analysed and the drilling parameters were optimized based on the test results.