Microstructure and Tribological Property of MWCNTs/Al Composites by Rotational Friction Extrusion Process

Abstract

The aluminum matrix composites reinforced with the multi-walled carbon nanotubes (MWCNTs) were fabricated by rotational friction extrusion (RFE) process and the microstructure, hardness and tribological property of the composites were investigated. The results show that the bulk composites with certain dimension can be fabricated by the RFE process. The microstructure of the composites appears as fine equiaxed grain after dynamic recrystallization and the quality is good. The MWCNTs are uniformly distributed in the composites. The hardness of the composites increases firstly and then decreases with the increase of MWCNTs. When the volume fraction of MWCNTs is about 4%, its hardness is about 20% higher than that of the original Al matrix material by RFE process. The lubrication and wear resistance of the composites are changed with the addition of MWCNTs. With the increase of the MWCNTs, the wear rate of the composites is decreased at first, and when the volume fraction of MWCNTs is more than 3%, the wear rate varies little. The wear mechanism is changed, which is from adhesion wear and mild abrasive wear to the delamination wear and abrasive wear with the increase of the MWCNTs.

Keywords

• rotational friction extrusion
• composite
• microstructure
• tribological property
• wear mechanism