The improvement of the ductility in the friction stir-welded Al-1.0Si-0.5Mg-0.1Mn (mass%) alloy sheet in T4 temper was investigated to develop a tailored blank that has superior press-formability. The fracture position during the tensile test shifted from the HAZ to the base metal, and the elongation increased by the reversion heat treatment at 523K for 0 seconds immediately following FSW. Additionally, the maximum forming height in the cup-drawing test improved. If the temperature during natural aging between FSW and reversion heat treatment was 293 K, the aging time of up to 2 hours was acceptable for the ductility improvement. Moreover, the ductility improvement was maintained for over 30 days at 293 K and within 15 days at 313 K after reversion, however, the fracture position during the tensile test shifted to the stir zone after 30 days at 313 K. Improvement in ductility was also achieved by applying reversion heat treatment before FSW. These improvements were considered to the result of differences in the natural aging properties at the stir zone, HAZ, and base metal.

In this study, the effect of secondary-phase particles on microstructures and creep properties of A2618 aluminum forged and then T61-tempered alloy was investigated by creep test, tensile test, SEM (Scanning electron microscopy)-EBSD (Electron backscatter diffraction) measurement, and X-ray diffraction analysis. Two samples with differently distributed secondary-phase particles were prepared by permanent-mold casting (MC) and furnace cooling within graphite crucible (FC). Steady-state creep rate was smaller and creep rupture time was prolonged in MC sample with denser and finer secondary-phase particles, and grain boundary strengthening by the particles was found to be responsible for the improved creep properties of MC sample. The result of in-situ heating SEM-EBSD measurement suggested that more notable recrystallization through particle-stimulated nucleation occurs in MC sample, resulting in the refined recrystallized grains with a higher coverage ratio of secondary-phase particles along grain boundaries.

A hardened sheet of 3104 aluminum alloy is used for the beverage can body stock. In this material, controlling the ear of the circular deep-drawn cup is important to prevent can forming defects. Previous studies have shown that the friction force between the sheet material and the forming die affects the earing behavior during circular deep-drawing, in addition to the plastic anisotropy of the material. However, the effect of the anisotropy of the friction coefficient remains unclear. In this study, I investigated the effect of friction force anisotropy on earing behavior of the hardened sheet of 3104 alloy by circular deep-drawing test. This results that the ear profile changes by friction coefficient anisotropy. Moreover, I calculated the ear profile using the elementary method of analysis (or slab method). This analysis leads to the following conclusions: (1) The angle to rolling direction of ear is determined by plastic anisotropy, i.e., in-plane anisotropy of Lankford value, work hardening exponent and plastic strength coefficient. However, the relative height relation of ears and valleys in a cup cannot be explained by only the parameters. (2) Regarding the balance of cup ear and valley, the friction coefficient anisotropy affects. These determine the final ear profile.