Research On Technology Of Ultrasonic Assisted Microchannelarray Formation In Pure Aluminum

With the development of technology,some physical field-assisted microforming processes have been rapidly developed,including electromagnetic-assisted microforming,current-assisted microforming,and ultrasonic-assisted microforming.At present,studies have shown that ultrasonic vibration-assisted microforming can reduce the material forming load through its volume effect and surface effect,thereby increasing the plastic deformation capacity of the material.However,compared with the research on ultrasonic-assisted polymer material micro-molding technology has been relatively mature,ultrasonic assisted metal material micro-molding process research is still relatively small.Pure aluminum cylinders prepared by the wire cutting process is used in this paper,and different heat treatment processes are used to obtain pure aluminum with different grain sizes.The size effect of the microcompression test,and the use of ultrasonic vibration and vibration power to the effect of the experimental stress-strain curve is studied.Abaqus software was used to simulate the micro-molding test,the experimental process and the influence of various process parameters were analyzed.Ultrasonicassisted micro-molding tests and ultrasonic-assisted micro-channel array tests on pure aluminum were conducted to study the influence of various process parameters on the micro-molding test and micro-channel array experiments,and the mechanism of ultrasonic vibration on the filling behavior.In the process of micro-compression of pure aluminum,the flow stress of the material decreases with the decrease of the size of the sample at different heat treatment temperatures.It shows a significant size effect.Ultrasound is applied to samples of different sizes and grain sizes.After vibration,the true stress-strain curve of the material is reduced,that is,the ultrasonic vibration produces a softening effect on the material,the decrease in the true stress-strain curve of the material increases with the increase of the ultrasonic power.The numerical simulation analysis of the micromolding test and the microchannel array test of pure aluminum were carried out to study the effects of groove width,friction coefficient,reduction and ultrasonic vibration on the filling height.The results show that the width and the reduction have the greatest influence on the filling height.Obviously,the filling height increases linearly with the increase of the groove width and the reduction.In addition,with the decrease of the friction coefficient,the filling height will increase.When there is no friction,the front of the forming rib is relatively straight.When there is friction,as the material is subjected to the frictional force of the groovesidewalls,an arc will appear at the front of the fored ribs.The ultrasonic-assisted micromolding test was simulated.The results show that the Mises stress and the maximum true strain of each part of the formed part are reduced after ultrasonic application.The influences of process parameters such as reduction,groove width and ultrasonic vibration on the micro-molding test of pure aluminum were studied.The results show that with the increase of the reduction,the filling height also increases linearly.With the increase of groove width,the filling height increases first and then decreases,and the relative filling height does not change much.When the groove width is 0.3 mm,the filling height increases with the increase of the grain size,when the groove width is 0.1 mm,the filling height increases first and then decreases.Because the filling of the material becomes more difficult when there are only a few crystal grains in the groove width direction.Ultrasonic-assisted micro-molding tests show that ultrasonic vibration will improve the filling effect of the material.microchannel array forming test of pure aluminum was conducted to study the influence of process parameters and ultrasonic vibration on the forming process.The study shows that with the increase of the reduction,the filling height l increases linearly,as the width of the groove increases,the filling height of increases first and then decreases.As the grain size increases,the filling height increases first and then decreases,and as the mold duty cycle increases,the filling height decreases.Ultrasound-assisted microchannel array tests show that ultrasonic vibration will improve the filling effect of the material,including increase the filling height,make the height of each area of the array piece more uniform,and improve the shape of the forming ribs to fit the shape of the mold more.