Jintao Li

Effect of Magnetostatic Field on Microstructure of 5005 Aluminum Alloy Sheet by Roll-Casting

The roll-casting technology of 5000 series aluminum alloy is one of the difficulties at present. Roll-casting technology was employed in this paper and high quality 5005 aluminum alloy sheets were fabricated successfully under different conditions. The solidification of melt in roll-casting process is the rapid directional solidification. The effect of magnetostatic field on microstructure of 5005 aluminum alloy sheet by roll-casting has been investigated and analyzed. The results indicate that imposing magnetostatic field can refine the grains of 5005 aluminum alloy.

Optimization and application of process parameters in an AZ61 alloy twin-roll strip casting

Twin-roll strip casting is a concerned technology for economically producing magnesium alloys sheets. In this paper, numerical simulation of the twin-roll strip casting of an AZ61 magnesium alloy was carried out and the optimal process parameters were obtained. Then, under the conditions obtained through simulation, AZ61 strips of good surface quality were successfully manufactured. The microstructure of the alloy by twin-rolled strip casting is obvious refined compared with that by conventional casting.

A Study on the Aluminum Alloy AA1050 Severely Deformed by Non-Equal Channel Angular Pressing

In order to improve the efficiency of grain refinement, a study on the modified process (called Non-equal channel angular pressing) from the conventional equal channel angular pressing has been conducted. The deformation behavior of aluminum alloy AA1050 deformed by the Non-equal channel angular pressing which has a smaller width in the exit channel than the entry channel was examined based on the finite element simulations. The results revealed that a smaller ratio of dE and dI (dE/dI) leads to a larger equivalent plastic strain. It is not only beneficial to enhance the plastic deformation but also very helpful to get rid of the development of dead zone in the outer corner of die by decreasing the exit channel width by comparing with the conventional process.

On the Influence of Mesh Size during Finite Element Simulation of Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) has attracted a lot of interest due to its ability for fabrication of bulk ultrafine-grained materials. With the development of computer skills, the computer-aided methods become very important and useful in understanding the deformation mechanism of ECAP. In this study, the influence of mesh size during finite element simulations of ECAP has been examined based on the plane strain condition assumption. Four different meshes have been compared and these results indicate that Mesh 600 and Mesh 2400 fail to capture the deformation features of ECAP accurately. Large corner gaps develop in these two cases and the simulated strains are smaller than the analytical calculations. Similar results have been obtained between Mesh 6369 and Mesh 12000 and the predicted features of plastic deformation and texture evolution are consistent with the experimental results.

Investigation of Deformation Behavior during Cold Rolling Cladding Process of Four-Layer Composite Aluminum Alloys

Two different types of aluminum alloys of AA5005 and AA6061 were used to fabricate four-layer laminated composite materials by the cold rolling cladding technology. The original sheet metals were annealed at 500 °C for three hours to achieve equiaxed microstructures, with an average grain size of 50 µm for AA5005 and 38 µm for AA6061. Tensile tests of these two alloys have been conducted and the results were used as the input parameters to build the finite element model. The influences of sample assembling order and frictional conditions on the deformation behavior have been studied in the present work. In the experiments, very good bonding with no delamination between four layers was attained. Similar hardness has been observed for both AA5005 layer (about 79.6 Hv) and AA6061 layer (about 80.3 Hv) in the laminated composite materials.

Effect of Electromagnetic Field on Microstructure of 5052 Aluminum Alloy Sheet by Roll-Casting

The effect of electromagnetic field on microstructure of roll-casting 5052 aluminum alloy sheet has been investigated and analyzed. The results indicate that imposing static magnetic field can refine the grains of 5052 aluminum alloy during the roll-casting; accordingly, imposing static magnetic field and alternating current at the same time, the grains are remarkably refined and equiaxed due to electromagnetic oscillation effect.