Hanlin Ding

Investigation of the hot compression behavior of the Mg?9Al?1Zn alloy using EBSP analysis and a cellular automata simulation

In this paper, the flow behavior of the magnesium alloy AZ91 during hot compression with dynamic recrystallization (DRX) is studied by the electron back-scattered diffraction pattern (EBSP) method and a two-dimensional cellular automata (CA) simulation. The flow behavior characteristics of the alloy during compression are studied and analyzed in detail. The influence of second phase particles on the accumulation of dislocation and the migration of grain boundaries during the compression process are taken into account in the CA model. The current CA simulation results agree well with the experimental data in terms of both flow stress and microstructure evolution, suggesting that the proposed CA model is a reliable numerical approach for studying the DRX process of the AZ91 alloy. The simulated results show that the average size of the recrystallized grains increases to a peak value and then slowly reduces to a steady value due to simultaneous multi-cycle recrystallization during hot compression of the AZ91 alloy.

FEM modeling of dynamical recrystallization during multi-pass hot rolling of AM50 alloy and experimental verification

The microstructure simulation during the multi-pass hot rolling of AM50 alloy was studied by DEFORM-3D. The excellent agreement with the experiment observations shows that the present modeling and user routine are feasible for the reproduce of the hot rolling process. The multi-pass hot rolling contributes to the achievement of a uniformly recrystallized microstructure with fine grains in the rolled sheet. The sheet temperature before the finish rolling strongly affects the final grain size, but hardly affects the grain size distribution. This modeling and the user routine also have a potential to be applied in the researches of the other multi-pass hot deformation process.

FEM analysis for hot rolling process of AM60 alloy

Abstract The rolling of AM60 sheets for 50% reduction was analyzed with DEFORM to investigate the hot deformation process. The simulated results show that the sheet velocities at the entrance (21 mm/s) and at the exit (37 mm/s) are less and larger than roll velocity, respectively. From the entrance to the neutral point, the velocity at the sheet surface is greater than that at the middle point of sheet in thickness, while that from the neutral point to the exit shows the opposite pattern. The effective strain of the sheet increases from the entrance to the exit due to the continuous reduction in thickness. In addition, the effective strain at the sheet surface reaches to 1.0 and is larger than that of 0.8 at the middle point of sheet. The difference of effective strain in thickness direction has a much stronger effect on the recrystallized fraction than on the recrystallized grain size. The minimum temperature of 347 °C is obtained at the surface contacting directly with roll and the maximum temperature 388 °C at the middle point of sheet in thickness.

Effect of calcium addition on microstructure and texture modification of Mg rolled sheets

The mechanical properties and texture of AM60 (Mg–6.0Al–0.3Mn, mass fraction %) and ZXM200 (Mg–1.6Zn–0.5Ca– 0.2Mn) Mg alloys subjected to multi-pass hot rolling were investigated. The finer recrystallized grains usually exhibit particular preferred orientations and then alter the total texture feature of rolled sheets. Ca solid solution into Mg matrix serves to the formation of texture component with c-axis rotated away from normal direction towards transverse direction and then weakens the overall texture intensity, resulting in a similar anisotropic characteristic to RE-containing Mg alloys.

Effect of finish-rolling conditions on mechanical properties and texture characteristics of AM50 alloy sheet

Abstract The conventional hot rolling of AM50 alloy at different roll temperatures and speeds was performed to investigate the effects of finish-rolling conditions on the mechanical properties and texture of rolled sheet. The better combination between strength (ultimate tensile strength: 295 MPa; yield strength: 224 MPa) and ductility (22.9%) can be obtained for the AM50 sheet rolled at the roll temperature of 200 °C with the roll speed of 5 m/min. The yield stress depends strongly on roll temperature, while the texture intensity in rolled sheets is more sensitive to roll speed during hot rolling. Increasing rolling temperature or roll speed can improve the mechanical anisotropy of AM50 rolled sheets.