Effect of Milling Speed on properties of Fe-NbC Composite Prepared by Mechanical Alloying

Nowadays, mechanical alloy (MA) method has turned up as one of a new and applicable method for metal matrix composite fabrication due to some advantages such as the ability to form nanocrystalline structure with improved properties. In this work, different milling speed of MA process (100, 200, 300 and 400 rpm) was performed on Fe-17.21wt%Nb-2.23wt%C with milling duration of 10 hours. The mixture was pressed and sintered at 1300 degrees C into a pellet form. Investigation by X-ray diffraction, measurement of hardness and density were carried out. High milling speed resulted on crystalline-to-amorphous transition of XRD peaks of Fe and NbC phases. Different level of MA at different speed also produced fine NbC particles and strain hardening which resulted in increase value of hardness. The presence of pores, particularly in the composite with high milling speed, decreased the density of Fe-NbC composite.