Abstract: An experimental instrument for simulating the roll-casting process was designed, and the effect of processing parameters on the microstructure of Al alloy was studied. Results show that with a specifically designed instrument equipped in a Gleeble-1500 Thermal Simulation Tester the typical microstructure with the characteristic of realistic roll-casting process can be obtained, and the microstructure is sensitive to the strain rate. When ε·=0.125s-1, the plastic deformation of Al alloy starts to couple with the solidification process, and the microstructure is of the roll-casting character. Whenε·=0.300s-1, the column crystals transform to equiaxed ones. The formation of roll-casting microstructure is mainly attributed to the deformation of un-solidified liquid phase, the varied distribution of mass and heat. Increasing the deformation velocity would do good to the formation of roll-casting microstructure and the equiaxed column crystals, and would decrease the rolling load.
Physical simulation of roll-casting microstructure of Al alloy
Abstract:
An experimental instrument for simulating the roll-casting process was designed, and the effect of processing parameters on the microstructure of Al alloy was studied. Results show that with a specifically designed instrument equipped in a Gleeble-1500 Thermal Simulation Tester the typical microstructure with the characteristic of realistic roll-casting process can be obtained, and the microstructure is sensitive to the strain rate. When ε·=0.125 s -1, the plastic deformation of Al alloy starts to couple with the solidification process, and the microstructure is of the roll-casting character. When ε·=0.300 s -1, the column crystals transform to equiaxed ones. The formation of roll-casting microstructure is mainly attributed to the deformation of un-solidified liquid phase, the varied distribution of mass and heat. Increasing the deformation velocity would do good to the formation of roll-casting microstructure and the equiaxed column crystals, and would decrease the rolling load.
Fig.1 Schematic diagram for physical simulation of roll-casting 1—Inlet and outlet of cooling media; 2—Quartz tube; 2—Aluminum ingot; 4—Copper foil; 5—Chuck; 6—Jig; 7—Control system of thermal simulation machine
图2 热模拟机夹头示意图
Fig.2 Schematic diagram of chuck of thermal simulation machine
Fig.5 Comparison of deformation curves between simulated roll-casting sample and actual aluminum alloy at different temperatures (a)—Sample No.1, 2 and 3; (b)—Sample No.4 and 5