Study On The Machinability Of Intermetallic Ti₂AlNb Alloy With High Pressure Cooling

The excellent mechanical properties of Intermetallic Ti₂AlNb alloy meet the new requirements for aerospace materials,which are in favor of improving the performance of aero-engine.However,because of the high specific strength and low thermal conductivity of Ti₂AlNb,the machinability of Intermetallic Ti₂AlNb alloy is poor.Due to the above problems,this paper studied the machinability of Intermetallic Ti₂AlNb alloy with high pressure cooling technology.This paper aimed to reveal the effect of high pressure cooling technology to improve the machinability of Intermetallic Ti₂AlNb alloy,through the study of cutting force,cutting temperature,chip morphology,tool wear and surface integrity,which could provide the basic data and theoretical basis for the subsequent research of high efficiency cutting Intermetallic Ti₂AlNb alloy.The main works of this paper are as follows:（1）In consideration of the concepts of the heat transfer theory,capillary boundary lubrication model and convection,the cooling and lubricating mechanism of high pressure cooling is described;Jet flow velocity simulation and cutting zone temperature field simulation were carried on with Fluent simulation software,which revealed that high pressure cooling can reduce the cutting temperature through weakening bubble adsorption phenomenon on the heat transfer surface.（2）Through the single factor experiment of turning Intermetallic Ti₂AlNb alloy,the influence of cutting parameters and cooling conditions on cutting force and cutting temperature was clarified.The remarkable cooling effect of high pressure cooling was revealed.（3）Through the orthogonal test,empirical formula for tool durability was obtained linear fitting method,and the effects of cutting speed and feed on tool wear were analyzed;The tool wear test illustrated the influences of cutting parameters and cooling conditions on tool life,tool wear and chip morphology.And the test revealed that high pressure cooling can decrease the tool wear and improve the performance of chip breaking.（4）Through orthogonal test and single factor test,the effects of cutting parameters and cooling conditions on the surface roughness,microstructure and residual stress were clarified,which revealed that high pressure cooling can achieve the decrease of surface roughness,the inhibition of white layer formation and the increase of surface residual compressive stress.