Papers by Author: Y.S. Song

Abstract: Uniaxial compression tests on hot-rolled AZ31 Mg alloy were carried out at a temperature of 300°C. In order to investigate work hardening and texture evolution during plastic deformation, cylindrical specimens were compressed to the rolling direction. Experimental investigation reveals that flow curves are strongly dependent on microstructure evolution such as deformation twinning and softening phenomenon. The occurrence of deformation twinning and softening phenomenon was revealed by the observation of microtexture using electron backscatter diffraction (EBSD). A visco-plastic self-consistent (VPSC) polycrystal model was used to simulate the work hardening, softening and texture evolution during the uniaxial compression. In order to calculate orientation of deformation twins, predominant twin reorientation (PTR) scheme was implemented into the polycrystal model. A softening scheme was also implemented in the polycrystal model to predict softening phenomenon and texture evolution after a peak stress.

Abstract: The evolution of hot rolling texture in FCC materials has been simulated numerically using a visco-plastic self-consistent (VPSC) polycrystal model. A finite element (FE) analysis with ABAQUS/StandardTM was conducted to evaluate the deformation gradients during hot rolling deformation. In order to capture crystallographic rotation during hot rolling deformation, an octahedral slip system was considered in a microscopic hardening model. The FE analysis with the VPSC polycrystal simulations successfully predicted the inhomogeneous texture development through the thickness direction in the hot-rolled Al-5wt%Mg alloy sheets.

Abstract: Evolution of crystallographic texture by hot rolling deformation at the temperature of 200°C was investigated by hot rolling tests on as-cast Al-5wt%Mg alloy fabricated by a new strip cast technology. Texture variation through the thickness direction in the Al-5wt%Mg alloy was examined experimentally. Macrotexture and microtexture measurements were conducted using X-ray diffractometer and electron backscatter diffraction (EBSD), respectively. Experimental investigation reveals that the evolution of texture and microstructure is strongly dependent on a distance from center of the Al-5wt%Mg alloy sheet. It was found that the shear texture components tend to be increased at the surface region of the hot-rolled specimen.