Experimental Study On Tool Wear Of γ-TiAl Alloy Milling Under ScCO₂-MQL

γ-TiAl alloy is characterized by high temperature creep resistance,high elastic modulus,and high specific stiffness and strength due to its light weight.The excellent physical properties ofγ-TiAl alloy make it important to be used in key parts such as engine blades and pneumatic stator and windscreen in aviation field.However,the machining performance ofγ-TiAl alloy is poor due to its properties.Needle chips are easily formed in the cutting ofγ-TiAl alloy.Severe bonding wear and high cutting forces will occur during machining.This causes rapid tool failure.In order to solve the problem of severe tool wear,the mechanical properties ofγ-TiAl alloy were studied.The cutting force ofγ-TiAl alloy was studied in combination with cutting simulation and milling experiment.The tool wear process and the chip shape under the condition of scCO₂-MQL were analyzed.The research content mainly includes the following aspects:Firstly,the mechanical properties ofγ-TiAl alloy were studied.The quasi-static compression test is conducted through the compression testing machine.Dynamic compression tests at different temperatures and strain rates were carried out using the Hopkinson pressure bar device.The change trend of mechanical properties ofγ-TiAl alloy was analyzed.At the same time,linear regression method is used to fit the data.The J-C constitutive model of the alloy was obtained.Secondly,based on the obtained constitutive model,the finite element simulation ofγ-TiAl alloy is established using ABAQUS software.Through the dry milling test ofγ-TiAl alloy,the cutting force and cutting vibration in the machining process are analyzed.In addition,the cutting force and chip shape of simulation and test results are compared to verify the fitted constitutive model.Finally,aiming at the serious tool wear problem inγ-TiAl alloy cutting,the milling research under supercritical CO₂-MQL is carried out.The tool wear mechanism is described in detail by means of dry cutting comparison.The influence of different machining conditions and cutting parameters on wear and chip morphology is discussed,which provides guidance for efficient milling ofγ-TiAl alloy.