Mechanical and tribological attributes of Al-CNT-Sn composites prepared by press and sintering

Abstract

Carbon nanotubes (CNTs) have shown tremendous progress during the past two decades due to their extraordinary properties. With CNTs added as an alloying element, various engineering materials exhibit better mechanical properties. Multi-walled carbon nanotubes (MWCNT) were synthesized in-house by chemical vapor deposition process. Carbon nanotube-reinforced aluminum composites were prepared by cold pressing (or compaction) and sintering using different fractions (0.5, 1.0, 1.5, and 2.0 weight percent) of MWCNTs. The Al-CNT composites consists of tin (Sn) at 1.0 wt.% in each composition. Tin promotes the sintering of aluminum matrix composite. The effect of CNT on the density, hardness, and wear behavior of the composites were studied. Wear tests were performed to determine friction and wear under dry, wet, and hot conditions under varying loads from 5 N to 20 N. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques were used for the characterization. This investigation shows that increased CNT content significantly improves the hardness and wear resistance of the composites. The friction and wear were found to increase with operating temperature. A significant reduction in coefficient of friction and wear rate was observed with the application of oil during the wear test.