Research On Cutting Technology Of Ti-Al Alloy Based On Temperature Control

Titanium aluminum alloy has the characteristics of low density,high strength,oxidation resistance,and high temperature creep resistance.It has great application potential in the aerospace industry and is a potential alternative material for titanium alloy and nickel-based superalloy.However,the material is sensitive to temperature.It is brittle at low temperature,and has strong plasticity and poor thermal conductivity at high temperature.Therefore,the cutting temperature is high,resulting in low processing efficiency,low tool life,and poor surface quality,which limits the application of the material.In this paper,aiming at the problem of the high cutting temperature of titanium aluminum alloy,the cutting technology based on temperature control is studied by using its temperature sensitive characteristics.The mechanical properties and constitutive equations of titanium aluminum alloy Ti-48Al-2Mn-2Nb,finite element simulation of cutting temperature field,material removal mechanism,and cutting surface integrity are studied.The static compression test,dynamic compression test,and dynamic shear test were carried out to study the static and dynamic mechanical properties of the material.The fracture characteristics of materials under static compression were analyzed by studying the metallography of static compression fracture samples.By studying the fracture of the Hopkinson impact specimens,the fracture characteristics of materials at different temperatures were analyzed.The JC constitutive equation of titanium aluminum alloy was fitted by the data obtained from static compression test at room temperature and the Hopkinson compression test.The influence of cutting speed on cutting temperature,and cutting force is revealed by comparing the chip morphology,cutting force and cutting temperature obtained by actual cutting test and finite element simulation.The evolution of chip morphology is studied,and the chip fracture is analyzed.Combined with the equivalent plastic deformation,stress field,and cutting temperature field obtained by simulation,the low temperature removal mechanism of the material is the combination of periodic fracture and adiabatic shear.Through the end face turning test of titanium aluminum alloy under three cooling conditions,the three-dimensional morphology and surface roughness of the machined surface were studied.The variation law of work hardening degree and hardened layer depth was analyzed.Combined with cutting temperature and material lamellar structure,the formation process of micro-defects on the machined surface was analyzed.The orthogonal cutting test of liquid nitrogen cooling was designed,and the prediction model of surface roughness of liquid nitrogen cooling cutting was constructed.