Study On Microstructure,properties And Thermal Deformation Behavior Of TA1-Q345 Composite Plate

Laminated composite can not only take advantage of the performance of their component materials,but also reduce the wasteful use of resources,so that they can simultaneously meet the dual advantages of performance and cost.The field is widely adopted.Explosive welding is a compound method that can achieve the same or different metals to be firmly combined in an instant,and is widely used in industrial production.Due to the severe plastic deformation of the explosive composite plate near the interface during the welding process,as well as deformation cracking and edge cracking in the subsequent deformation process,which seriously restricts its performance.Based on this,in this paper,the TA1-Q345 explosive composite plate was annealed in different processes to study the change of its microstructure and mechanical properties;and the structural performance of the composite plate under different deformation process parameters was studied by hot-press experiment,in order to expand the application range of TA1-Q345 composite plate and provide experimental data and theoretical guidance for the promotion and application of heterogeneous metal composite plate in production.Optical microscopy（OM）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,tensile testing machine and Gleeble-3500 thermal simulation testing machine were used for microstructure observation,chemical composition and mechanical properties analysis of TA1-Q345 composite plate,respectively.The main research conclusions as follows:After heat treatment,the order of formation of interface compounds in the Ti-Fe-C ternary system is from Fe Ti>Fe2Ti>Ti C.After welding,the interface of the TA1-Q345composite plate is periodically wave-shaped.When kept at a lower temperature（823k～973k）,the thickness of the interface diffusion layer is basically maintained at2.6μm;when the heat treatment temperature is increased to 1073k,the thickness of the diffusion layer increases to 3μm with the increase of temperature.The TA1 side near the interface is equiaxedα-Ti grain structure after welding,and the Q345 side is near the interface with elongated grains and away from the interface is equiaxed grains,and the grain size changes gradually,after 1073k×6h After heat treatment,the grains on both sides of the interface become equiaxed grains and the grain size increases compared with the explosive state.A large number of parallel dark gray parallel crystal bands were observed near Q345 side.After being kept warm for 6h at 1073k,the thickness of the strips increased from the initial 0.1μm to 200μm.The interface microhardness and bonding strength decrease with the increase of heat treatment temperature and holding time.After hot-press deformation,the flow stress of TA1-Q345 composite plate is positively correlated with strain rate and negatively correlated with deformation temperature.After the strain rate is 0.01s^-1,the deformation temperature is 573k～773k,and the compression is 50%,the interface waves and vortices become flat,and the tissues on both sides of the interface tend to be parallel along the deformation direction,and the uniformity of the tissue increases;The strain rate has little effect on the interface structure of the composite plate,and the structure is consistent with the explosion state.High deformation temperature,low strain rate and increased reduction can improve the deformation coordination of the composite plate.The constitutive equation of TA1-Q345composite plate under low strain rate was established by using modified J-C model,and its correlation coefficient R and average relative error AARE were 97.7%and 3.44%,respectively.