Study On Friction Pressure Shear Deformation Process Of 6061 Aluminum Alloy

Tube-rod materials are widely used nowadays.After experiencing various thermal processes,they often produce various structural defects.In order to obtain stable and reliable mechanical properties,it is very important to study the process of improving the internal structure of materials.The mechanical properties of the material such as uniform grain refinement and fatigue resistance of the structure can be obviously improved by severe shear deformation at high temperature.However,the traditional shear deformation processes,such as equal channel angular pressing(ECAP)or high pressure torsion(HPT),are often complicated and have many processes.In this paper,the structure of the high pressure shear device of the tube is simulated and designed.Friction pressure shearing deformation device is different from tube high pressure shearing device.It can realize severe deformation at different temperatures and different deformation quantities.It can simulate friction heat assisted rotary rolling deformation and has good practicability.Through the initial experiments,the specimens were designed as tooth-shaped structure.Taking 6061 aluminum alloy as the research sample,the finite element simulation model was established.By calculating and analyzing the temperature field,the optimum rotating speed and the optimum downward pressure rate were obtained.The temperature gradient of the specimens was better in the frictional heating stage,which facilitated the shear deformation.The shear deformation at high temperature was simulated by finite element method,and the optimum tooth number and thickness were obtained by optimizing the specimen shape.The effects of friction factor,rotation speed,rotation angle and torsion number on the forming quality and load were analyzed.The radial,axial strain and stress fields of the specimen after shear deformation were also analyzed.The results show that the shearing process of 6061 aluminum alloy is suitable for shearing deformation at the speed of 0.2 rad/s.With the increase of the torsion angle,the strain of the specimen increases gradually,and the maximum number of torsion cycles is 2.The deformation is characterized by the largest root position and symmetrical distribution on both sides.Finally,the microstructures and mechanical properties of the specimens were observed,and the reliability of the simulation and the feasibility of the device were verified,which provided guidance for process optimization and actual production.