Research On Ultrasonic Vibration Characteristics And Ultrasonic Cavitation Mechanism In Liquid Solder

With the development of modern industry,ultrasonic-assisted brazing technology has been widely used.By adding ultrasonic waves,this technology produces a cavitation effect inside the liquid solder,which can replace the flux to remove the oxide film on the surface of the base material,effectively avoiding the phenomenon of base material corrosion caused by the removal of the flux link and the residue of the flux.This article mainly studies the transmission law and vibration distribution of solid,liquid,and solid-liquid interfaces when ultrasonic waves are applied to the base metal and liquid solder,respectively.Under ultrasonic effects,different factors affect the growth and cracking of cavitation bubbles in liquid solder.Influence;A non-contact ultrasonic-assisted brazing model was designed,and the influence of different parameters on the surface vibration displacement of liquid solder was analyzed.Through the dynamic observation of the spreading process of the liquid solder when ultrasonic waves are applied to the base metal and the liquid solder,respectively,it is found that under the action of ultrasonic waves,the droplets of the solder spread to the surroundings.With time,the surface of the base metal liquid solders.The spread area of ??the material gradually increases,but the spread speed decreases in the final stage.The time required for the spreading of the solder under different amplitudes is different.The larger the applied ultrasonic amplitude,the faster the spreading speed,and the larger the amplitude of the base material and the surface of the liquid solder.Through the simulation analysis of the solid-liquid interface transmission law and vibration distribution when ultrasonic waves are applied to the base metal and the liquid solder,respectively.The study found that after applying ultrasonic waves,ultrasonic vibrations propagate outwards around the ultrasonic tool head.Although not pure sinusoidal vibrations,they also have certain characteristics such as periodicity,and the closer to the ultrasonic tool head,the greater the amplitude.When the ultrasonic wave is applied to the liquid solder,compared with the base metal,although the vibration intensity is less than the latter,the vibration of the surface of the liquid solder enters a stable time earlier,and the amplitude is more stable,which is more conducive to spreading.At the same amplitude,when the ultrasonic tool head is applied to the liquid solder,the ultrasonic vibration generated is less intense than when propagated in the base material,which is beneficial to the protection of brittle materials.Through the simulation analysis of the growth and rupture of cavitation bubbles of liquid solder under the action of ultrasonic waves,the cavitation effect in the three types of liquid solders gradually weakened with the increase of temperature;Difficulty caused by the effects of change.The smaller the initial radius of the cavitation bubble,the more obvious thecavitation effect.Based on the principle of non-contact ultrasonic generation of Lorentz force,simulation analysis of the formation and propagation mechanism of ultrasonic waves in ultrasonic-assisted brazing can be concluded that when the non-contact ultrasonic waves are applied,the internal vibration frequency of the liquid solder reaches 20 k Hz.Its surface vibrates,and the closer to the coil,the more obvious the displacement effect.The more turns of the coil,the greater the displacement of the surface of the liquid solder,and under the action of a large current.The effect of the number of turns on the surface of the liquid solder is more obvious.No matter whether a small current or a large current is passed in,the effect of the change in the residual magnetic field strength on the surface of the liquid solder is small in the horizontal direction,but the vertical Lorentz force produced by it is beneficial to the soldering connection.The greater the current flowing into the coil,the greater the displacement on the surface of the liquid solder.The larger the current frequency,the larger the displacement of the surface of the liquid solder in the X and Y directions,but the smaller the vibration of the center of the solder.