Production of Fe-C Powders with Improved Structure

Production of Fe-C alloy powders by mechanical alloying was studied. Fe and graphite elemental powder mixtures containing 0.8 and 1.5wt.% graphite were mechanically alloyed using a planetary ball mill. The structural changes of powder particles during mechanical alloying were studied by x-ray diffractometery, scanning electron microscopy and microhardness measurements. For both compositions, mechanical alloying for 30h resulted in the development of a nanocrystalline structure with a typical grain size of 16nm containing nanoscale size Fe3C phase. This structure exhibited high microhardness value of the order of 600Hv. The powder particles after 30h of milling had a nearly spherical morphology and narrow size distribution. The mean powder particle size for Fe-0.8wt.% graphite composition was 15μm, whereas the Fe-1.5wt.% graphite composition achieved a smaller particle size with a mean of 9μm due to higher graphite content.