| TC4 titanium alloy is widely used in automotive,aerospace and medical equipment manufacturing due to its high specific strength,good thermal stability and strong corrosion resistance.Many countries have recognized the importance of titanium alloy materials,and have researched and developed them successively,TC4 titanium alloy have been applied in practice.Titanium alloy has small thermal conductivity and elastic modulus,which leads to low machining efficiency,high processing cost and the quality of machining is difficult to guarantee.The development of high-speed grinding technology has created conditions for solving this problem,but due to random distribution of grains,the mechanism of mechanical and physical phenomena between the abrasive grains and the workpiece material is complicated during the grinding process,The research on the mechanism of high-speed grinding has become extremely difficult.In this paper,the single abrasive grain in the high-speed grinding process are used as the research object to observe and study the grinding force,material pile-up,wear debris shape and wear surface characteristics during the grinding process,which provides a theoretical basis for complex grinding research.The main research contents are as follows.(1)The tensile test was carried out at room temperature to obtain the relevant mechanical properties of titanium alloy materials at different tensile speeds.The Johnson-Cook constitutive model of TC4 titanium alloy was optimized and modified.The friction and wear tests of titanium alloys at different grinding speeds were carried out,and the friction factor was measured.The above work paved the way for titanium alloy grinding simulation.(2)The geometry of the single abrasive grain during the grinding process is simplified,and the final geometry is determined to be conical.The grinding force,the grinding track and the thickness of the debris are theoretically analyzed during the grinding process.The path of the single grain which accorded with the actual grinding trace has been proposed.Accordingly,the test device was designed and developed for the high speed grinding with single grain.(3)The Deform-3D software was used to simulate the process of grinding TC4 with a single abrasive.The influence of grinding parameters on the grinding force was analyzed.The influence of the negative rake angle of the abrasive on the shape of the grinding debris and the grinding process parameters were analyzed.The results show that the grinding force decreases with the increase of the grinding speed and increases with the increase of the grinding depth.With the increase of the negative rake angle of the abrasive grains,the shear angle of the wear debris is continuously reduced.The degree of slippage increases,the thickness of the wear debris increases and tends to be flat.As the grinding speed increases,the stacking height on both sides of the wear scar tends to decrease,the burr flanging phenomenon is smaller,and the surface quality is better.Grinding depth increases material accumulation significantly,and burr cuffs become more prominent.(4)The CNC Machining Center was employed in the process of High speed grinding Ti6Al4 V with single abrasive grain.The grinding force was monitored by a 3D dynamometer,the material Pile-up and surface characteristics were observed with a 3D profilometer and scanning electron microscope(SEM).The material Pile-up ratio,surface micro topography and sub-surface plastic deformation of the scratch were analyzed.The shape of scratch presents a smooth spindle surface profile,there is a large amount of material pile-up on the sides and the outlet end of the grinding scratch.The material pile-up ratio is the largest at the end of scratch and at the middle of scratch pile-up ratio is the smallest.The wear forms of the scratch surface are adhesive abrasion and abrasive grain abrasion.The sub-surface shows obvious plastic deformation,and the ? phase is elongated and refined during the grinding process,it tends to be parallel to the grinding direction. |
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