Sliding wear behavior of Cr–Mo–Cu alloy cast irons with and without nano-additives

Abstract

• The nano materials were used to modify the performance of alloy cast iron. • The hardness of alloy cast iron with nano-additives increased greatly. • The wear resistance of alloy cast iron with nano-additives increased notably. • The grinding efficient of alloy cast iron with nano-additives was dramaticlly better than that of alloy cast iron without nano-additives. In this paper, the microstructures of Cr–Mo–Cu alloy cast irons with and without nano-additives were characterized by scanning electron microscope (SEM) and energy diffraction spectrum analyser (EDS). The dry sliding wear tests were carried out using a pin-on-disk wear tester against GCr15 steel balls under fixed normal load and rotating velocity. The study aimed to illustrate the effect of graphite morphology on the sliding wear behavior of Cr–Mo–Cu alloy cast irons. The experimental results showed that the graphite morphology of Cr–Mo–Cu alloy cast iron is affected by nano-additives. They are transformed from thick-long flake to thin-short vermicular shape, and the hardness increased notably. The wear test results indicated that the wear rate of Cr–Mo–Cu alloy cast irons decreases with addition of nano-additives while the wear rate of the GCr15 steel ball worn against with the alloy cast iron modified by nano-additives increases. The graphite morphology plays a significant role in the wear performance of the alloy cast iron. The analysis of worn surfaces and wear debris indicated that the dominant wear mechanism for the alloy cast iron without nano-additives is adhesive wear and plough. However, the percent of oxidation wear mechanism for the alloy cast iron with nano-additives increases.