The Key Technologies And Experimental Research Of ECAP

The equal channel angular extrusion(Equal Channel Angular Pressing,ECAP)which based on the large plastic deformation theory is a kind of effective method to produce bulk ultra fine-grained materials.But nowadays,the current research is still in the process on the micro structure and properties of alloy materials,the development of extrusion equipment,the detection and control of extrusion parameters and its practical application in the industrial field has made little progress.Therefore,based on the above problems,the ECAP extrusion process under different parameters were simulated and the influence of different technological parameters were investigated.The equal channel angular extrusion die and special equipment and its control system are designed and developed,which in order to improve the success rate and efficiency of the ECAP process and finally speed up the process from laboratory to practical application.Firstly,the ECAP finite element model is established by ANSYS with different die structural parameters,the ECAP process were simulated by using the finite element model.According to the simulation results,the variation and distribution of friction stress and inner equivalent plastic strain for specimen with different die structural parameters were investigated.Secondly,the theoretical calculation formula of extrusion pressure in ECAP process is determined,the finite element simulation of equal channel angular extrusion pressure of AZ31 magnesium alloy with different extrusion parameters was carried out by using DEFORM-3D.The extrusion pressure under different extrusion parameters was obtained,and the variation of the extrusion pressure with different parameters was investigated.Thirdly,the equal channel angular extrusion die and the special ECAP extrusion equipment were designed and developed,and the hardware and software of the equipment control system were designed and carried out.Fourthly,the ECAP process for AZ31 magnesium alloy was carried out by using the special equipment.The appearance of the specimens with different parameters and the variation of the extrusion pressure are compared with the simulation results,and the finite element simulation results were proved.The effect of different extrusion parameters on the grain refinement is analyzed.