Research On Microstructure Evolution And Interface Bonding Mechanism Of Solid Metal Shear Bonding

Solid metal bonding has become a widely used method in many industries.With the continuous development of science and technology and the emergence of new materials and new parts,the traditional way of bonding metal plates has been unable to meet the needs of modern production efficiency and technology.The new solid metal shear bonding process has the advantages of innovative technology,good manufacturability and low cost,so that it has a good application prospects.In this paper,the shear bonding experiments between Q345 and Q345,42CrMo and40CrNiMo steel were carried out.The microstructure of interface,the mechanical properties of joints,the diffusion of interface elements and the tensile fracture surface were studied.The influence of deformation process on the microstructure of deformation zone was also investigated.The results show that the reduction and shear rate have important influence on tissue change and connection strength.With the increase of the amount of reduction,the interfacial grains gradually form finer equiaxed grains through the dynamic recrystallization mechanism,and the interface voids are gradually closed to form the bonding joints,and the connection strength of the joints is improved.With the increase of shear bonding speed,the degree of grain refinement is reduced.There is element diffusion in the interface,and the properties of the material have important influence on the diffusion degree.The thermal simulation compression test of Q345 steel with deformation temperature of 900??1100?,strain rate of 0.01s^-1?10s^-1 and deformation of 0.6 was carried out by using Gleeble-3800 testing machine.The high temperature flow stress curve of Q345 steel was obtained,and the constitutive equation and dynamic recrystallization model of hot deformation of Q345 steel were established by mathematical modeling;The dynamic recrystallization model of Q345 steel was compiled and embedded by using the secondary development function of Deform-3D numerical simulation software,and the dynamic recrystallization behavior of the interfacial interface was simulated.The numerical simulation results show that with the increase of shear reduction,the dynamic recrystallization volume of interfacial grains increases and the average grain size decreases obviously.The validity of numerical simulation of microstructure of shear interface is proved by microstructure analysis and verification of shear interface,which can be used as reference for the microstructure evolution of shear interface.