The effect of powder and processing variables on the microstructure of an extruded FeAl (40 at%) alloy has been investigated. Results show that at low extrusion temperatures, where grain boundary mobility is low, grains do not grow beyond the prior particle oxide boundaries, and grain size is dependent upon the powder size and size distribution. At higher extrusion temperatures grain boundary mobility is high and powder size is not very critical. It was also found that for a given powder size, increasing the extrusion temperature increases the grain size. In addition to powder and processing variables, the effect of a 1 vol7o Y_2O_3 dispersion was investigated. The microstructure of the dispersed alloy extrusions were very fine grained even at high extrusion temperatures.By manipulating powder and processing parameters, a large range of microstructures were obtained. This enabled an evaluation of the role of microstructure and grain size on the room and high temperature mechanical properties of this alloy. Room temperature tensile data of the as extruded materials revealed that those with the finer grains had the highest yield strengths and ultimate tensile strengths as well as tensile elongation. At elevated temperature (HOOK) the coarse grained materials exhibited larger yield strengths in tension with the exception of the very fine grained oxide dispersion strengthened (ODS) extrusion, which had the highest yield strength despite its small grain size.
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