Whisker orientation controls wear of 3D-printed epoxy nanocomposites

Abstract

Additive manufacturing enables design of multi-material composite materials with tunable mechanical properties. Previous studies on epoxy-based composites containing silica, clays or fiber showed that favorable mechanical properties can be achieved by controlling the fiber orientation and architecture. In this work the effect of the build direction and whiskers orientation on the wear properties of 3D printed epoxy-based nanocomposites is investigated. Epoxy-nanoclay-PTFE-SiC nanocomposites are fabricated using a direct-write additive manufacturing method that enables one to orient the SiC whiskers along the printing path. Tribological results show that variations in build direction and whiskers orientation relative to the sliding direction cause anisotropy in wear and friction in these nanocomposites. The best wear performance was achieved with the nanocomposites printed with whiskers oriented perpendicular to the sliding steel counter-surface and slid orthogonally to the build direction and print path orientation. All nanocomposites had significantly better wear properties than the unfilled epoxy sample. The results suggest that optimizing the whisker orientation and alignment in epoxy-based nanocomposites through direct-write additive manufacturing increases the wear performance. This enables an additional design paradigm when optimizing multifunctional, 3D-printed epoxy nanocomposites.