Study On High Speed Impact Welding By Laser Controlled Energetic Materials

In recent years,with the rapid development of new energy batteries,microelectronics manufacturing,semiconductors,aerospace and other fields,the required materials for corrosion resistance,electrical conductivity,thermal conductivity and other material properties have higher requirements,the properties of single metal materials have been difficult to meet the needs of development;In addition,the material size requirements also tend to be more thin,small.In order to solve the above problems,Al/Cu high speed impact welding experiments were carried out by laser controlled energetic materials.At the same time,the microstructure of welding interface,the formation mechanism of interface wave and the dynamic process of welding were studied by numerical simulation.The main work and achievements are as follows:Firstly,the principle of interaction between laser and energetic material is explored,and the prerequisite conditions of high speed impact welding and the formation mechanism of interfacial wave are summarized.The conditions for the generation of impingement jet at the interface of high speed impingement welding are also studied.Secondly,Al/Cu high-speed impact welding experiments were carried out when the laser energy was 587 m J,652 m J,717 m J,920 m J and 1280 m J,and the energy containing materials of the ablative layer were blank group,black paint,black tape,diesel oil and titanium film.The laser energy parameters were 717 m J,920 m J and 1280 m J.When the energetic material of the ablative layer is black paint,the welding is realized successfully.By SEM detection of the microstructure of the bonding interface of the experimental welds,it is found that when the laser energy is 717 m J,920 m J and1280 m J,the interface waveforms of the welding bonding interface are flat,microwave and wavelet,and the bounce-back phenomenon occurs at the welding bonding interface and the bounce-back edge cracks.The EDS line scanning test showed that the content of aluminum and copper showed a regular "X" shape,and there was element diffusion at the welded interface,and the thickness of diffusion layer was about 1.8μm.Finally,the smoothed particle hydrodynamics(SPH)method was used for numerical simulation.The simulation results show that the rebound phenomenon occurs in the center of the welding bonding interface,and the welding bonding area is located on both sides of the rebound area,which is consistent with the experimental results.The generation of impact jet is related to the impact Angle and impact velocity.When the impact Angle is too small,the jet cannot be generated.With the increase of impact velocity,the jet flow will increase significantly.At the same time,it is also found that the jet basically comes from flyer plate aluminum,because the density of flyer plate aluminum is much less than that of base plate copper,and the jet mainly comes from materials with low density.In addition,it is found that the formation of welding interface waves is caused by the erosion and penetration of jet particles on the base and flyer plates.