Effect of MWCNTs content and sintering atmosphere on microstructure and various properties of Iron-MWCNTs MMC fabricated by conventional powder metallurgy

Abstract

The present research 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 ultrasonication followed by planetary milling 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 1200 and 1300 °C for 2 h in argon and hydrogen atmospheres. The milled powder and sintered composites were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Raman spectroscopy. It has been observed that MWCNTs are stable; retain their tubular structure both after milling and consolidation. The optimum relative density, hardness and compressive strength of 86 %, 170 HV and 425 MPa were found in Fe-4 vol% MWCNTs composite respectively when consolidated in argon gas at 1300 °C for 2 h. The maximum electrical conductivity of 6 × 10⁶ S/m was achieved in 2 vol% MWCNTs composite consolidated at 1300 °C for 2 h in argon gas. The iron-MWCNTs composites exhibit higher wear resistance and corrosion resistance than pure iron.