| Compared with single-phase reinforced aluminum matrix composites,multi-scale particle hybrid reinforced aluminum matrix composites have the advantages of high specific strength,high specific modulus and wear resistance,which are of great significance for achieving lightweight aerospace structures.Thermoplastic processing is a key step for composite materials to change from raw materials to structural parts,and has a significant impact on the organization and properties of the workpiece.In this context,this article carried out related researches on the thermoplastic deformation behavior of Ti B2·Ti Al3/2024Al composite materials,taking the Ti B2·Ti Al3/2024Al composite materials prepared by in-situ method as the research object,establishing constitutive model and thermal processing Figure;finite element simulation of composite multi-directional forging by Deform-3D;multi-directional forging experiment to verify the simulation results and study the influence of multi-directional forging process parameters on the structure and properties of Ti B2·Ti Al3/2024Al composite material.Firstly,the Ti B2·Ti Al3/2024Al composite material was prepared by the in-situ method,and the composite material was subjected to isothermal compression using the Gleeble-3500 thermal simulation tester at a temperature of 300?500?and a strain rate of 0.001?1s-1 Experiment to study the high-temperature rheological behavior and microstructure evolution of composite materials.The main strengthening mechanisms of different reinforcing particles in the composite material are discussed.The results show that Ti B2 is nano-sized reinforcing particles,and the Ti B2 reinforcing particles distributed on the grain boundary mainly play the role of fine-grain strengthening and load distribution strengthening.Ti Al3 belongs to the micron-sized reinforcing particles,which mainly plays the role of fine-grain strengthening,thermal mismatch strengthening and load distribution strengthening.On the basis of the G-Z constitutive model,considering the strengthening mechanism of two kinds of reinforcement particles,a constitutive model that can accurately reflect the thermal deformation behavior of composite materials is established.Based on the stress-strain curve of the composite material,the thermal processing map of the composite material at high temperature was established,and the deformation mechanism of the different regions in the steady state zon of the thermal processing map and the instability zone were determined.It is found that the plastic instability zone of the composite material is concentrated at 300?400?,the strain rate is greater than 0.05s-1,and the best thermal deformation conditions are 450?500?,0.001?0.1s-1.Multi-directional forging simulation of composite materials was carried out by Deform-3D software,and the influence of different forging temperatures and forging passes on the dynamic recrystallization behavior of composite materials was explored.The results show that recrystallization mainly occurs in the X-shaped large deformation zone composed of the central part and four sharp corners.As the temperature increases and the number of forging passes increases,the recrystallized volume fraction of the billet increases,and the grains of the billet are refined.When the forging pass reaches three passes,the internal recrystallization of the material is basically completed,and the grain refinement effect is significant.Finally,a multi-directional forging experiment was carried out on the composite material to analyze the influence of different forging temperatures and forging passes on the structure and properties of the material,and to verify the finite element simulation results.The results show that multi-directional forging can improve the distribution of reinforcing particles in the matrix,reduce the agglomeration of reinforcing particles,and refine the grains.The room temperature tensile test of multi-directional forging specimens under different process parameters was carried out,and it was found that multi-directional forging can significantly improve the mechanical properties of composite materials.This subject has studied the thermoplastic deformation behavior of composite materials through the preparation of Ti B2·Ti Al3/2024Al composite materials,the strengthening mechanism of composite materials by different reinforcing particles,the thermal deformation behavior of composite materials,multi-directional forging finite element simulation and experimental verification.It is of great significance to the thermoplastic processing and organization control of composite materials. |
PDF Full Text Request