Abstract
Metal injection molding (MIM) was applied to Al powders. Sintered Al compacts were prepared by MIM in this study. At first, sintered pure-Al compacts were prepared under various process conditions. The relative densities of the compacts debound in Ar gas and sintered at 650 °C for 2 hr in vacuum of 10−3 Pa order were 86 %, 90 % and 96 % when the average particle size were 20 μm, 10 μm and 3 μm, respectively. The 3 μm powder compact had the excellent tensile strength of 120 MPa and elongation at fracture of 19 % at room temperature. Next, the addition of Si powder to Al powder was examined to improve sinterability of Al powder. Regardless of Al powder size, the addition of Si powder widely enhanced densification of sintered Al compacts. Using Al powder of 35 μm, the relative density of the sintered pure-Al compact was only 66 %, while that of the sintered Al-1 mass%Si compacts went up to 89 %. When Al powder of 11 μm was used, the sintered Al-1Si compacts had the relative density of 97 % and the tensile properties close to annealed wrought pure-Al.
