Abstract
In order to compare the thixoformability between granular crystal structures and dendrite crystal ones of aluminum alloy billets produced by the semisolid and conventional DC continuous casting. The thixoforming test was performed at a constant deformation speed of 4 mm/s in an argon atmosphere. The test piece consisting of granular crystals of AA356,AA6070 and AA7075 alloys reveals that the thixoforming power was less than 1kN during three quarters of forming process and the maximum power at the final stage was about 20kN. In contrast, the test piece consisting of dendrite crystal structure reveals that the power was more than 5kN at the first stage and as the forming process proceeded, the power increased. The maximum power at the last stage was about 30kN. Granular grains of primary α aluminum coexisting with the liquid phase were possible to move easily into the die cavity, because the liquid phase played an important role of lubricant as the thixoforming was performed to the semisolid slurry.
