4 research outputs found
Effect of Texture of AZ31 Magnesium Alloy Sheet on Mechanical Properties and Formability at High Strain Rate
The mechanical properties and formability of AZ31 magnesium alloy strips having different textures were investigated at a high strain rate based on that occuring in mass production by press forming. Forming at a high strain rate on the order of 10 0 s À1 requires a high temperature of over 473 K. To obtain accurate stress-strain curves, a high-speed testing machine that can maintain a constant true strain rate was used, and the change in gauge length on a test piece in a furnace was measured during the testing time of about 0.5 s. For the specimens, rolled strips consisting of fine grains (about 10 mm) and an extruded strip consisting of coarse grains (about 40 mm) were used. The {0001} textures of the extruded strip and one of the rolled strips were strongly oriented parallel to the rolled surface, but the texture of another rolling strip had two peaks that were inclined at 5 2:2 was obtained under uniform heating above 503 K in all the specimens except for the extruded strip. The high LDR of the rolled strip having a two-peak texture was maintained in forming at temperatures down to 473 K, in contrast to the LDR of the strongly oriented rolled strip, which reduced rapidly when formed at temperatures less than 503 K
Domestic or overseas trend in research and development of magnesium alloy plastic processing
Rolling Texture Evolution of AZ31 Magnesium Alloy Sheets by Isothermal Eccentric-Rolls Drawing
Changes of Shape and Stress Distribution during Free Bulging in Axisymmetrically Blow-Formed Superplastic Sheet *
Changes in the shape and stress distributions during free bulging in axisymmetrically blow-formed superplastic sheets are analyzed. Generally, the shape is assumed to be spherical and the stress distribution is a function satisfying only boundary conditions without any theoretical bases, because of the nonlinear constitutive equations of superplasticity. An assumed stress distribution function gives a particular pressure distribution on the workpiece. If the pressure distribution is uniform, the function represents a true distribution of stress. Such a function is proposed in this paper and is verified by the analysis without these additional assumptions. With progress in forming, all areas except those in the neighborhood of the periphery approach the equi-biaxial tensile stress state and the entire shape approaches that of a hemisphere