Microstructural characterization, mechanical properties, electrical conductivity and corrosion studies of Fe-MWCNTs composite fabricated by conventional powder metallurgy

Abstract

The present study reports the fabrication of MWCNTs reinforced (0.5, 1, 2, 4 vol. %) iron metal matrix composites by conventional powder metallurgy. The composites were fabricated by ultra-sonication for 3 hours followed by planetary milling of 20 min in a dual-drive planetary ball mill (DDPM) to obtain uniform dispersion of MWCNTs into iron matrix. The milled powders were then cold compacted and sintered at 1300 C for 2 hours in Ar atmosphere. The milled composite powder and sintered composites were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and Raman spectroscopy. It has been observed that MWCNTs are stable, maintained their structure after milling and consolidation. The optimum density, hardness and compressive strength of 86 % relative density, 170 HV and 425 MPa respectively were found in Fe-4 vol. % MWCNTs composite. The non-lubricated sliding wear behaviour of the composites against a diamond ball was studied. The wear depth and possible wear mechanisms were investigated. The electrical conductivity of fabricated composites was evaluated and found that conductivity increases with increasing MWCNTs. The corrosion behaviour of the composites was studied in 3 wt. % NaCl solution. Fig. 1 (a) and (b) show the density and compressive stress-strain plots of Fe-MWCNTs composites.