Effect Of Single Point Friction Thermal Incremental Forming Process Parameters On Formability And Parts Properties Of AZ31B Magnesium Alloy

Friction thermal incremental forming is one of the local heating methods in incremental forming,which can simplify the forming equipment and provide heat for the forming process.Among them,friction heat refers to the heat generated by the severe friction between the tool head and the sheet metal,and its size is related to various process parameters of incremental forming,including spindle speed,tool head diameter and drop,etc.The formability and properties of sheet metal depend on the microstructure of sheet affected by friction heat and process parameters.Therefore,in this paper,the influence of friction thermal incremental forming process parameters on the forming ability and part properties of AZ31 B magnesium alloy sheet is explored by using friction thermal incremental forming experiment,finite element simulation technology,metallographic observation,tensile test,hardness test and X-ray diffraction analysis.The main research contents and experimental results are as follows:The finite element simulation results show that the Mises stress,Equivalent plastic strain and Thickness in the corner region are quite different from those in the sidewall region;The drop and tool head diameter have no significant effect on the maximum Mises stress,and the maximum Mises stress fluctuates between 160 MPa and 180MPa;The equivalent plastic strain and drop are positively correlated,but negatively correlated with the tool head diameter.The thickness of the part is negatively correlated with the decrease,while the thickness increases first and then decreases with the increase of the tool head diameter.The two-way trajectory improves the uniformity of equivalent plastic strain and thickness distribution.Metallographic observation,tensile test,hardness test and X-ray diffraction show that the higher the forming height is,the more refined grains are in the microstructure;The finer grains in the corner area are more than those in the side wall area,and the hardness of the corner area is greater than that of the side wall area;The greater the spindle speed and the drop,the more refined grains are;The increase of the drop will improve the tensile strength and hardness of the side wall area,and reduce the elongation;The increase of the spindle speed and the drop will increase the elongation of the side wall area;The increase of spindle speed can improve the tensile strength,elongation and hardness of the side wall area;The correlation between the diameter of tool head and the microstructure,tensile strength,elongation and hardness of AZ31 B magnesium alloy is weak.In the process of friction heat incremental forming of AZ31 B magnesium alloy,the main crystal plane involved in the slip deformation is the base plane(0002),and there is no new slip system to participate in the slip deformation of magnesium alloy,which only affects the degree of each crystal plane involved in the slip deformation;Increasing the spindle speed can indirectly improve the degree of each crystal plane involved in the slip deformation of AZ31 B Magnesium Alloy by increasing the temperature in the deformation zone.