Tensile properties of as-deformed 2A50 aluminum alloy were investigated in the high temperature solid and semi-solid states.The results show that temperature has almost no effect on the maximum tensile stress between 500 °C and 530 °C, and the maximum tensile stress decreases rapidly when the temperature is above 532 °C.The ductility decreases with increasing temperature and has an obvious fall when the temperature is above solidus temperature.This alloy almost has no ductility above 537 °C, and cannot sustain tensile stress above 550 °C.A brittle temperature range in which this alloy is prone to form microcracks was derived.The relation between microstructure, fraction solid and tensile properties were also investigated by examining the metallograph and fracture surface morphology of tested specimens, which could provide reference for forecasting the microcracks in this alloy occurring in semi-solid processing.
The semi-solid filling-plastic flowing integrated forging process of semi-solid 6061 Al alloy was simulated by commercial finite element software DEFORM-3D.Temperature,fluid and stress-strain fields were considered in numerical simulation.The simulation results show that the plastic deformation of billet of the ends is higher than that of billet in the straight cylinder.The value of plastic deformation varies with loading mode and plastic deformation fields at the stage of increasing pressure to constant value.When the thixoforging experiments were performed at 590 ℃,15 mm/s of punch velocity and 46 MPa of pressure side urn,it gets the filling wholly and dense internal organization of semi-solid thixoforging parts is gotten.Finite element analysis results are compatible with experimental ones.
