摘要
Hot forming with synchronous cooling(HFSC)is a novel technique for heat-treatable,high-strength aluminum alloys,which allows the alloys to acquire good formability,negligible springback,rapid processing and better mechanical properties.However,the deformation behavior and microstructure evolution of the alloys during HFSC are complex and need to be studied due to the temperature and strain rate effects.Uniaxial tensile tests in a temperature range of 250—450℃and a strain rate range of 0.01—1 s-1 for AA2024-H18 aluminum alloy sheet are conducted with a Gleeble-3500 Thermal-Mechanical Simulation Tester.And based on metallography observation and analysis,AA2024-H18 aluminum alloy sheet in HSFC process exhibits hardening and dynamic recovery behaviors within the temperature range of 250—450 ℃.Strain rate shows different effects on ductility at different temperatures.Compared with traditional warm/hot forming methods,AA2024-H18 aluminum alloy achieves a better work-hardening result through HFSC operations,which promises an improved formability at elevated temperature and thus good mechanical properties of final part.After HSFC operations,the microstructure of the specimens is composed of elongated static recrystallization grain.
Hot forming with synchronous cooling （HFSC） is a novel technique for heat-treatable, high-strength a luminum alloys, which allows the alloys to acquire good formability, negligible springback, rapid processing and better mechanical properties. However, the deformation behavior and microstructure evolution of the alloys during HFSC are complex and need to be studied due to the temperature and strain rate effects. Uniaxial tensile tests in a temperature range of 250 450 ℃ and a strain rate range of 0.01 1 s-1 for AA2024-H18 aluminum alloy sheet are conducted with a Gleeble-3500 Thermal-Mechanical Simulation Tester. And based on metallography observa tion and analysis, AA2024-H18 aluminum alloy sheet in HSFC process exhibits hardening and dynamic recovery behaviors within the temperature range of 250 450 ~C. Strain rate shows different effects on ductility at different temperatures. Compared with traditional warm/hot forming methods, AA2024-H18 aluminum alloy achieves a better work hardening result through HFSC operations, which promises an improved formability at elevated tem perature and thus good mechanical properties of final part. After HSFC operations, the mierostructure of the spec- imens is composed of elongated static recrystallization grain.
基金
supported by the National Natural Science Foundation of China(No.51175252)
