Effects of Pre-strain and Deformation on Microstructure Evolution and Mechanical Properties of Aluminum Alloys for Dampers during Hot Forming Process
摘要
In the present study, aiming to optimize process parameters, the influence of pre-strain and deformation on microstructure evolution and mechanical properties have been studied in detail for aluminum alloy material for dampers. The results show that the increased pre-strain promotes the occurrence of recrystallization and the acceleration of precipitation kinetics. The dislocation density increased with the increasing pre-strain, which is responsible for the high fraction η' phase. The specimen in the condition of 5% pre-strain and 5% deformation amount exhibits the high volume fraction fine η' phase, corresponding to the ultimate tensile strength/yield strength values of 580 MPa and 532 MPa. Large pre-strain leads to the coarsening of the η' phase and the formation of more equilibrium η phase, which reduces the precipitation strengthening effect and results in a decrease in strength. After the calculation of strengthening mechanism, the specimens in 5% pre-strain and 5% deformation amount and the specimen in 0% pre-strain and 10% deformation amount are dominated by precipitation strengthening and dislocation strengthening.