Research On The Technology Of Connecting Aluminum/carbon Fiber Materials To The Interlayer Of Laser Ignition Al-Ti System

With the global advocacy of energy conservation and emission reduction,carbon fiber composites have gradually become one of the indispensable materials in the lightweight process of vehicles.The structural parts of single metal materials have gradually developed into a combination of heterogeneous materials,which makes the heterogeneous connection technology between metal and carbon fiber composites become a research hotspot with high research value and application prospect.In this paper,the connection experiments of aluminum and carbon fiber materials?CFRTP?are carried out by using the interlayer of Al-Ti system.The interlayer used in this experiment is optimized,and the reaction process of high temperature self-spreading in the interlayer is analyzed.The effects of different process parameters on the macroscopic morphology,microscopic morphology and mechanical properties of joints were studied by single factor and experimental optimization method.The optimum parameter combination is obtained,and the connection mechanism of the joint is expounded.The results show:The minimum starting temperature of self-spreading reaction in the interlayer of Al-Ti system is 610K,when the carbon content n is 0.3<n<1.3,the self-spreading reaction can be self-sustaining and no gasification phenomenon,the interlayer self-spreading reaction begins with the melting of aluminum powder,first carries on the Al-Ti reaction to generate Al₃Ti and a small amount of Al₂Ti,and then occurs the Ti-C system with high exothermic heat,The Al₃Ti-C system reacts and generates TiC and Al.The connection effect using Al-Ti interlayer is poor,and there are a lot of defects in the joint.The joint quality obtained by using Al-Ti-C interlayer is excellent,and the interface structure is aluminum/Al₃Ti+Al₂Ti+TiC+Al/CFRTP.In the interlayer component,the increase of carbon content makes the Al₃Ti tissue change from plaque to coarse branch,the granular TiC tissue increases and becomes larger,and the shear strength of the joint increases first and then decreases.With the increase of the density of the interlayer,the density of the joints is increased,the shear strength of the joints increases first and then is flat,but when the interlayer is dense,the interlayer products appear unevenly distributed.With the increase of the connection temperature,the effective connection area becomes larger,the bubble size in the CFRTP is larger and moved up,and the shear strength increases first and then decreases.The increase of the connection pressure makes the crack of the CFRTP side joints smaller,the shear strength increases first and then is flat,but the excessive connection pressure will lead to the serious overflow of the molten substrate and destroy the integrity of the CFRTP's own structure.The optimum process parameters are combined with the interlayer component Al40Ti53C7?n=1.2?,the interlayer density 80%,the connection temperature 1600°C,the connection pressure 30N,and the maximum shear strength of the joint is 13.65MPa.The mechanism of the aluminum/CFRTP laser ignition self-spreading connection is:After the laser induced the interlayer,the reaction begins and releases the heat to form the combustion wave,the combustion wave is transmitted to the aluminum side,the aluminum and the interlayer are fused and diffused to form a bonding interface.When the connection temperature reaches the condition,the CFRTP is pressed on the interlayer with a certain connection pressure.The heated melting CFRTP and the interlayer have the effect of elemental diffusion and anchoring,and when the temperature is lowered to room temperature,a good quality aluminum/interlayer/CFRTP joint is formed.