Cu-based MoS2-dispersed composite material formed by the compression shearing method at room temperature

Abstract

Cu/MoS2 composite material was formed by a novel powder-molding technique, which is termed the compression shearing method at room temperature (COSME-RT). Cu/MoS2 sample mechanical and tribological properties and microstructures were investigated. Samples were prepared using five different MoS2 concentrations between 0 to 20 vol.%. No unwanted compounds were generated by the Cu and MoS2 because a high temperature is unnecessary in COSME-RT. Scanning electron microscopy observations confirmed that the MoS2 particles were dispersed homogeneously in the Cu host matrix. The indentation hardness of Cu/MoS2 with 0, 1.0 and 5.0 vol.% MoS2 was higher than 1.6 GPa, and is higher than that formed by conventional powder metallurgy methods and a pure Cu plate. The indentation hardness of the Cu/MoS2 decreased with increasing MoS2 concentration. In contrast, the lubricating performance of MoS2 became more pronounced at 5.0 vol.% or above. The coefficient of friction of Cu/MoS2 with 5.0, 10 and 20 vol.% MoS2 was ∼0.20, and is the same as for MoS2 in air. The sample coefficient of friction was maintained because of lubrication by forming a transferred film of wear debris that contained MoS2. Cu/MoS2 had a low coefficient of friction, but maintained its material strength at 5.0 vol.% MoS2.