Through Hole Aluminum Fabricated by the Extraction of Lubricated Metallic Wires

Abstract

Through holes, which provide flow paths for coolants, are useful in the cooling panels of the turbine blades of airplane jet engines and the heat sinks of electronics devices in cars and computers. To date, through holes have been fabricated by the directional solidification of molten metals having dissolved hydrogen, the core-bar pulling method, the rod-dipping process, mechanical drilling, electron beam and laser ablation processing, and other processes. However, the fabricated holes are short and impractical. The aspect ratio of the length to the diameter of holes in aluminum is at most 10. Here we report through hole aluminum fabricated by extracting lubricated metallic wires embedded in a solidified aluminum melt. X-ray computed tomography showed that the through holes are very long with a maximum aspect ratio of 270. The hole sizes range from 10² to several 10³ µm in diameter. Furthermore, the present technique can fabricate spiral and V-shaped holes in aluminum, a capability lacking in conventional perforation techniques. Thus, our methodology for producing through hole metals is expected to provide expanded opportunities for technologies such as heat sinks, turbines, biomaterials, and machine tools.