The Study Of Ni/Al Multilayer And Its Welding Application

With the development rapidly of the miniaturization of weapon system,nano reactive multilayer is one of hot topics about energetic multilayer material,which is in order to meet the energy requirement of energy devices.Reactive energetic multilayer is applied in slapper detonator and hypervelocity launcher.Energetic multilayer will release a great deal of heat when the multilayer is reacted,which could achieve the joining of different material.It is a new joining technology,which is paid more and more attention in recent years.The welding technology is mainly to join ceramic,metal,intermetallic compound and amorphous compounds,which are hard to join by common welding technology.The different multilayer and technological parameter have significant influence on the welding performance.The study choose Ni/Al multilayer as the energetic multilayer,which is fabricated easily and have a lot of release heat compared with CuO/Al,Pt/Al,Ti/Al and so on.Ni and Al alternating nanolayer were deposited by DC magnetron sputtering in this study,and the high temperature heat released and the products by the multilayer membrane reaction were used to weld the Al₂O₃ ceramics and metal copper.Al₂O₃ceramics is a kind of engineering ceramic material with a variety of excellent properties,such as low thermal expansion coefficient,high thermal conductivity and high mechanical strength,nice temperature resistance,good strength and hardness,excellent wear resistance,corrosion resistance and high temperature resistance.It has a broad application prospect,but its high brittleness greatly limits its use.The metal,such as copper,has a high strength and toughness,ductility,thermal conductivity.So it is significant to realize the connection between Al₂O₃ ceramics and copper to get the composite material applied in real life.In this investigation,the joining of copper to alumina of dissimilar materials was benignly achieved using Ni/Al multilayer as interlayer at low temperature without extra pressure under nitrogen protection by transient liquid phase diffusion bonding.Sound joints and the interface microstructure of the joints were obtained at 550°C using Ni/Al multilayer and AuSn solder.The strength of the joint produced without Ni/Al multilayer is very low,while the strength was significantly improved for the bond performed utilizing Ni/Al multilayer,increasing from 0.13 to 17 MPa.And the shear strength is increasing by the temperature rising,and the max shear strength of reached 88 MPa at750?,which attests all solid-state diffusion rates and the magnitude of diffusion increase as the temperature rises during the joining process,enhancing the shear strength.