Simulation And Microscopic Analysis Of Laser Welding Of Silicon Alminum Alloy

In recent years,silicon aluminum alloy has been widely used as microwave electronic packaging materials.The thermal expansion coefficient of the silicon aluminum alloy material is small and the thermal expansion coefficient of the silicon plate is similar to that of the electronic device.The density is lower than that of the microelectronic encapsulation material such as the kavelan alloy,and it has a high thermal conductivity as the aluminum alloy.By adjusting the percentage of silicon in aluminum content can be made of different properties of silicon aluminum alloy.Microwave devices are precision electro nic devices,small size,sealing temperature can not be too high,and not suitable for welding methods such as arc welding.The laser has a high energy and a small heating area allows the electronic packaging material to be welded and sealed.However,there are large chalcopyrite particles in the silicon aluminum alloy material and a thin layer of oxide layer on the surface,which causes the leakage failure of the weld ing cavity,and the control of the welding process parameters also affects the welding effect.Firstly,in this paper,the microanalysis technology is summarized.The principle of scanning electron microscopy and energy dispersive spectrometer is briefly introduced.The comparison between secondary electron imaging and backscattering imaging of silicon aluminum alloy Al4047 shows that the difference of the secondary electron imaging and backscattered imaging,and simply refer to the silicon aluminum alloy welding line scan,the line scan application was introduced.Secondly,the failure of the three kinds of silicon aluminum alloy materials made by the failure of the packaging cavity analysis,resulting in cavity leakage failure is mainly due to two reasons: 1)silicon aluminum alloy material is not suitable for welding;2)improper welding operation to generate cracks,pores,Slag,weld coverage is not complete lead to leakage of the packaging cavity.By the use of SEM and EDS failure analysis means,we can study the two causes of failure and put forward the means to improve product qualification rate.Thirdly,the alloy cavity composed of silicon aluminum alloy 4047 cover plate and aluminum alloy 6061 shell was welded.By changing the welding process parameters,the influence of different process parameters on the weld pool shape was obtained.Finally,the finite element simulation of the silicon-aluminum alloy cavity was carried out.The plate model and the cavity model were established in ANSYS software respectively and the Gaussian heat source was selected as the laser heat source model.The temperature distribution and stress distribution of the flat plate under the specified welding conditions were obtained by the plate model.The shape of the molten pool and the temperature and stress distribution on the two sides of the weld were obtained.Furthermore,the simulation of the cavity model is carried out,and the whole temperature and stress distribution are analyzed.