Noah Utsumi

Surface Nitriding of Al-Mg Alloys Using a Rotary Barrel Tank

The authors developed a new nitriding process to form an aluminum nitride film on a pure aluminum surface. In this study, a rotary barrel polishing method was applied to gas nitriding in an attempt to form an aluminum nitride film on the surface of Al-Mg alloys. Nitriding was carried out at 823 K, 853 K, and 873 K for 3.6 ks to 25.2 ks. Alumina- and aluminum - 50mass% magnesium powders were used as the media that flowed in the barrel tank. An aluminum nitride film was formed on the aluminum alloy surfaces within a relatively short time. The effect of the treatment temperature on the formation and growth of the aluminum nitride was investigated. It was found that the formation and growth of the aluminum nitride film were greatly affected by differences in the Mg content in the aluminum substrate and by the treatment temperature.

Bending Method for Forming Curvature and Various Cross-Section Shapes

Previous studies on the bending process of extruded aluminum alloys have focused on a high-precision bending process that controls various undesirable phenomena. In contrast, this paper proposes a new bending method in which undesirable deformations are intentionally occurred and can be deformed into an arbitrary cross-sectional shape. By bending the extruded section, we sought to establish a novel bending process, in which a curvature and cross-sectional shape are produced in a single process. Undesirable deformations that occur by bending channel materials with a removed tensile flange include both the outward and inward deformations of the webs. Based on such deformations, this report proposes several types of cross-sectional shapes that can be formed through simulations and press bending experiments.

Formation of Aluminum Nitride Films by Gas Nitriding

In this study, aluminum alloys were subjected to nitriding at 823 K for 0–18.0 ks using alumina and magnesium powders for improving their radiation performance. After nitriding, aluminum nitride films were formed on the aluminum substrate. The thickness of the formed films varied from 1.5 to 11 μm, and the color of the film surface was dark brown or black. The thickness of the aluminum nitride film increased with an increase in the treatment time. X-ray diffraction and electron probe microanalysis results showed that the film was composed of aluminum nitride, alumina, aluminum, and magnesium. Further, the film showed good adhesion at 0 ks.