This study explores the manner in which quenching temperature during furnace cooling affects the aging properties of Al-Zn-Mg alloys following solution treatment. The microstructure formed during furnace cooling at temperatures below 373 K significantly influences the distribution of precipitates during the aging process. Therefore, understanding the structural formation behavior during cooling is essential.

In this study, the effect of Cr addition on the corrosion resistance of aluminum was investigated by corrosion test, electrochemical measurements, and elemental analysis on surface of the specimens. The results of the corrosion test showed the mass loss significantly decreased by Cr addition. Furthermore, the corrosion morphology was similar between A1050 and Al-Cr alloy; however, the corrosion depth of the Al-Cr alloy was significantly shallower. Therefore, electrochemical impedance spectroscopy was performed to evaluate the change transfer resistance (R_ct) during corrosion test. The R_ct of A1050 changed to the lower value; however, Al-Cr alloy maintained the higher value in the corrosive environment. Before the corrosion test, the surface of Al-Cr alloy was covered with the natural oxide film free of Cr, whereas after the corrosion test, the film containing Cr was formed at the corroded site. It was considered that the high corrosion resistance mechanism of Cr addition is due to the high R_ct value observed in the corrosion environment, which is attributed to the Cr-containing film formed by corrosion.

Porous aluminum is aluminum with numerous pores inside, and is lightweight and has excellent shock-absorbing properties. Because of these characteristics, porous aluminum is expected to improve fuel efficiency and collision safety performance when used in structural components such as automobiles. However, it has disadvantages of low tensile and bending strength. In this study, we attempted to join polycarbonate plate (PCTA) and porous aluminum with dissimilar materials by friction welding. In order to clarify the softening behavior of PCTA and the impregnation behavior of PCTA into the pores of porous aluminum during friction welding, in-situ observation near the joining interface during friction welding was conducted by X-ray transmission. The results suggest that the area of softened PCTA can be controlled by indentation time, and that the upset pressurization is highly effective in promoting the impregnation of PCTA. When the area of softened PCTA became too large, there was less resistance during upset pressure, and PCTA was ejected as burrs from the joining interface.