Abstract
Effect of particle size distribution on the density and shrinkage of atomized ferrous alloy powder compacts were investigated by controlling particle size distribution of the two bimodal ferrous alloy powders (-25μm / 125-150μm, 25-46μm / 125-150μm). These powders were sintered at 1473K in vacuum after compacted at the pressure of 490MPa. As a result, the sintered compact of -5μm / 125-150μm bimodal powder with fine powder content of 35 mass% showed higher density and lower shrinkage ratio than those of other powder compacts. The improvement of particle packing depends strongly on the size ratio, mixing compositions of the fine to coarse powder. The density increase by the fine powder addition is considered to improve the mechanical properties of the sintered compacts without further addition of alloying elements.