Simulation Of Micro Arc Spark Deposition Based On Finite Element Method

The micro arc spark deposition technology is a green manufacturing technology.There is no pollution gas generated during processing,and it has good processing characteristics and has significant economic and environmental value.However,due to its complexity and randomness,it is difficult to find out its specific laws in actual experiments.Based on the finite element simulation method,the simulation model is obtained by simulating the temperature field of micro-arc spark deposition and verifying the experiment.And than,studying the characteristics and laws of micro-arc spark deposition process.(1)The finite element software is used to simulate the temperature field of micro-arc spark deposition,which shows that the highest temperature is much higher than its boiling point.It is considered that the pulse discharge not only melts the electrode and the matrix material,but also vaporizes the material to form discharge pits.It has also been found that the expansion of the single pulse temperature in the axial direction is deeper than in the radial direction.(2)Research on the base pit by the established simulation model.It shows that the melting width and penetration depth of the etch pit increase with the increase of current,but the variation of the melting width is obvious,so the shape of the pit is flat and semi-elliptical.The pit size also increases as the voltage increases,and at small voltages,the voltage has a greater effect on the pit size.(3)Comparing the single-point deposition experiments of titanium and iron-nickelchromium alloys,the results show that the micro-arc spark deposits show 3 appearances,which are divided into "splash" shape,"sticky" shape and "broken" shape.The feasibility of the model is verified by comparing the experimental and simulated pit size.(4)The simulation results show that the maximum temperature of 1 mm diameter electrode reaches tens of thousands of degrees,which is much higher than its boiling point;while the maximum temperature of 3 mm diameter electrode is 3295.02 ℃,the overall temperature is low,which is suitable for deposition temperature conditions,and in the process of processing,the range of temperature change is about 700 ℃,the temperature change is small.And the electrode temperature is low.The degree is relatively stable,so the deposition effect is good.Large frequency can easily make the electrode temperature rise rapidly,but it has no obvious effect on the temperature change range.Under the same loading time,the temperature distribution between 2464 ~2862 ℃,which means that the easy-to-process temperature range is large and easy to deposit,is larger when the cooling time is first large and then small.(5)Under the same parameters,the micro-arc spark deposition simulation of TA2 and Fe-Ni-Cr alloy shows that the temperature of TA2 is about 2.5 times of that of Fe-Ni-Cr alloy,and the temperature is much higher than its boiling point.At the same time,the cooling rate of TA2 is much higher than that of Fe-Ni-Cr alloy at the initial stage of 100 to 200 μs,which is about 3 times as fast as that of Fe-Ni-Cr alloy.This causes TA2 to solidify easily and produces rough surfaces during spreading.In this paper,the simulation model of micro-arc spark deposition is found through experiments and simulations.The influencing factors of the size of the discharge pit and the temperature field distribution of the electrode and the substrate during the processing are found.This paper finds out the rules that cannot be detected in the actual processing.Subsequent research on the temperature distribution of multiple deposition spots can improve the simulation accuracy.