Effect Of Ultrasonic-DC Magnetic Coupling On Microstructure And Properties For A356 Aluminum Alloy

As one of the most widely used light alloys at present,aluminum alloys are widely used in aerospace,automobile wheels,shipbuilding and other industrial applications due to their strong plasticity,high strength,easy processing and good mechanical properties.However,in the actual production process,defects such as pores,inclusions and shrinkage holes are likely to occur inside the aluminum alloy,which will seriously affect the overall property of the aluminum alloy.In this paper,the ultrasonic field,magnetic field and acousto-magnetic coupling field are used to process Al-Si-Mg aluminum alloy(abbreviated as A356 aluminum alloy,the same below).Firstly,ultrasonic field treatment was used to investigate its influence on the microstructure and properties of the alloy,and the optimal ultrasonic treatment parameters were determined to be ultrasonic waves of 150 W applied at670 ℃ for 180s;Secondly,DC steady magnetic field processing was used to determine the optimal magnetic field,and the processing parameters were applied at670℃ with 2600 W DC steady magnetic field for 180 s.Finally,the acoustic-magnetic coupling field was used for processing,and the experiment results were compared with the experimental results of single ultrasonic field and DC steady magnetic field.The results show that when an ultrasonic field or a DC steady magnetic field is applied in the melt of A356 aluminum alloy,the microstructure of the alloy is significantly refined when a 150 W ultrasonic field or a 2600 W DC magnetic field is applied at 670 ℃.The hardness,conductivity and compression property are of the alloy is improved.When the ultrasonic field or magnetic field power continues to increase,the processing time increases,and the processing temperature is higher,the alloy structure shows a roughening trend and each property is decreased.This is mainly due to the ultrasonic cavitation effect,acoustic flow effect and electromagnetic stirring,it caused fine-grained strengthening and the strengthening of the second phase.However,as the reaction continues,cavitation acoustic flow or electromagnetic stirring effects will gradually weaken,which will affect the refinement and property.Therefore,after the introduction of the acousto-magnetic coupled composite field,the energy of the two external fields can be collected at the same time,so as to achieve optimization and improvement of the alloy structure and property in a short time.The experimental results show that the effects of fining grain and improving property can be achieved by applying 100 W ultrasonic power,1300 W magnetic field power for180 s at 670℃.