Abstract
Synthesis and consolidation of an iron-aluminide, Fe3Al, via powder metallurgical route has been studied. A mixture of elemental powders of iron (75at%) and aluminum (25at%) is charged into a vibratory ball mill and milled for eighty hours. X-ray diffraction shows that the mechanically alloyed powder consists of crystalline iron and non-crystalline aluminides and that it changes into a single phase of Fe3Al during following hot consolidation processes. To otain fully dense Fe3Al compacts, several hot consolidation techniques, including uniaxial hot compaction, hot upsetting, hot pressing, hot extrusion and hot isostatic pressing, are examined. Among these processes, HIP is the most superior consolidation technique to obtain products with full density and good mechanical properties. Although uniaxial hot consolidation and hot upsetting are not suitable for higher densification, substantial densification is achieved in hot pressing and hot extrusion; for example, the density of 95-97% of the theoretical value is obtained by extruding compacts at temperatures above 1150°C. Addition of 5wt% of aluminum oxide particle brings increases in hardness and 0.2% proof stress without any loss of ductility.
