Simulation And Experimental Study On Machining Process Of Ni₃Al Based Superalloy

Ni₃Al-based superalloys are an intermetallic compound alloy based on Ni₃Al.Because they are also a typical difficult-to-machine material,there are problems such as large cutting force and serious tool wear during cutting,and there are few studies on cutting processing.This has hindered the further application of Ni₃Al-based superalloys to some extent.Therefore,it is of practical significance to study the cutting process of Ni₃Al-based superalloys.In this paper,the cutting process of the matrix monocrystalline Ni₃Al is studied by molecular dynamics method.The phenomena occurred were analyzed.Then the cutting tests of Ni₃Al-based superalloy were carried out.The test results were analyzed.The results of the cutting tests and the molecular dynamics simulation results were compared and analyzed.The specific works and research results of this paper are as follows:1.The molecular dynamics three-dimensional model of high-speed cutting monocrystalline Ni₃Al with spherical diamond tool was established.In order to make the cutting process more realistic,the appropriate potential energy function,ensemble and atomic motion equation were selected,and the relevant calculation parameters were determined to guarantee calculation efficiency.2.The cutting process simulation of high-speed cutting of monocrystalline Ni₃Al workpiece by diamond tool was carried out.The formation of cutting chips and machined surfaces,cutting groove morphology,lattice deformation,cutting force,workpiece temperature and system potential energy were analyzed during the cutting process.The results show that the formation of the chips and the machined surfaces is due to the pushing actions of the tool,which is mainly related to the actions of the tangential force and the normal force.The shape of the cutting grooves on the surface of the workpiece is wide in the front and narrow in the back.The workpiece temperature and system potential energy are gradually increased,and the elastic recovery and lattice reconstruction of the machined surface will reduce the rate of increase.The lattice deformation and reconstruction of the workpiece atoms will result in fluctuations in cutting force,workpiece temperature and system potential energy during the cutting process.3.In order to further explore the influence of cutting parameters on the cutting process of monocrystalline Ni₃Al,the simulations with different cutting speeds and depth of cut were carried out.The effects of cutting parameters change on chip accumulation,lattice deformation,groove morphology,cutting force,workpiece temperature and system potential energy were investigated.The results show that the increase of cutting speeds has little effect on the chip accumulation and the range of lattice deformation of the workpiece atoms,the depth of cut increases,the accumulated chips and the area where the workpiece undergo lattice deformation increases significantly.The cutting parameters change,the shape of the groove is still wide in the front and narrow in the back,and the cutting speeds increase,the difference between the front and the back of the groove increases first and then decreases;the depth of cut increases,and the width difference between the front and the back of the groove shows a decreased trend.The average cutting force,workpiece temperature and system potential energy increase with increasing cutting speeds and depth of cut.4.The cutting tests of different cutting parameters of Ni₃Al-based superalloy were carried out.The change of real-time cutting force during the cutting process was obtained.The groove morphology of the sample surface after cutting was detected.The test results show that the material accumulation on both sides of the cutting groove on the surface of the sample is different,and there are less accumulation on both sides of the cut position of the groove,and more accumulation in the middle and the cut-out position;the increase of speed will reduce the height of the material accumulation on both sides of the groove.The increase of the depths of cut increase the height of the material accumulation on both sides of the groove;the overall change trend of the cutting force during the cutting process is first increased and then decreased,which is compatible with the cutting path;and the cutting force decreases with the increase of the cutting speeds and increases with the increase of cutting depths;the cutting test and molecular dynamics simulation are consistent in some results,which verifies the correctness and effectiveness of the molecular dynamics simulation.