Research On High-efficiency Resistance Brazing Technology Of C/C Composite-T2 Copper

C/C composite is a carbon fiber reinforced carbon based composite.It has many advantages,such as light weight,high strength,high modulus,good fracture toughness and wear resistance at high temperature,and it is widely used in many fie lds.The connection of C/C composite and copper is used in international thermonuclear reactor.With the development of the Internet of things and the Internet,automation and intelligent manufacturing are the prospective development trends.Considering the electric characteristics of the C/C composites,the resistance brazing has the characteristics of short cycle,low labor intensity and high effic iency,so the process and connection mechanis m of the C/C composite /T2 copper resistance brazing is studied in this paper.This paper first explored the positive reverse resistance brazing of C/C composite /T2 copper,and the reason why the reverse resistance brazing is superior to the forward resistance brazing is preliminarily analyzed.Then through the orthogonal experiment,it was found that the welding current had the greatest influence on the shear strength of the C/C composite /T2 copper resistance brazing joint,the welding pressure was the second,the welding time had the least infl uence on the shear strength of the joint.According to the sequence of welding current,welding pressure and welding time,the changes of the interfacial microstructure and mechanical properties of C/C composite/T2 copper brazed joint are investigated,and the maximum shear strength of the welding joint reaches 11±2MPa,and the optimum process parameters are welding current 8kA,welding pressure 500 N,welding time 60 ms.Finally,the fracture is analyzed.The fracture is mainly broken at the middle layer,and partly broken on C/C composites.In order to further improve the strength of C/C composite /T2 copper resistance brazing joint,the influence of AgCuTi filler metal with different Ti content on the joint forming,interface structure and mechanical proper ties of resistance brazing joints is first explored.It is found that the joint formed when the content of Ti is 6% was better,the reaction layer is the thickest,and the joint strength is the highest,which is 14±2MPa.Subsequently,the possibility of formation of various compounds(TiC and Ti-Cu compounds)in the reaction layer was explained from the thermodynamic point of view.The AgCuTi resistance brazing C/C composite /T2 copper joint interface atom diffusion growth model was established and the growt h process of the interface reaction layer was e xpounded..It was found that the increase of Cu in the solder still inhibited the viability of Ti,So at last,we explored C/C composite/T2 copper resistance brazing when Ti plate acts as interlayer.It is found that a certain wetting angle is formed at the joint of the C/C composite /T2 copper copper.The thickness of the reaction layer and the shear strength of the joint increase with the increase of the thickness of the Ti foil.When the thickness of the Ti foil is 80?m,the shear strength is 21±1MPa.