(János Bolyai Research Scholarship of the Hungarian Academy of Sciences.)
The failure of artificial joints is often attributed to wear, prompting researchers
to explore effective solutions such as material improvement, surface texturing and
coating. This study introduces a novel approach of employing 3D printed Voronoi structures
to enhance lubrication in polymer-metal sliding wear, with the aim of extending the
longevity of artificial joint systems. Specifically, this study investigates the relationship
between the geometries and tribological properties of Ti6Al4V Voronoi structures,
paired with ultra-high-molecular-weight polyethylene (UHMWPE). The results indicate
that the void size in Voronoi structures can be manipulated to match the feature size
in the surface texturing approach, suggesting the potential to induce the hydrodynamic
effect for friction reduction. The effect of Voronoi structures on reducing friction
and wear was examined using pin-on-disc (PoD) tests. In comparison to the control
group of solid pins, implementing Voronoi structures in the pins decreases the mean
values of static coefficient of friction (COF), dynamic COF, and wear volume by 24.6
%, 29.4 %, and 51.2 %, respectively. Indistinct trends were observed between the COF
and the geometric parameters of Voronoi structures. It is hypothesised that interconnected
porosity networks within Voronoi structures may preserve wear debris and retain lubricant,
potentially elevating hydrodynamic pressure and thereby improving the friction condition.
Moreover, comparative analysis of the wear tracks confirms the effective wear reduction
achieved by Voronoi structures, with abrasion identified as the primary wear mechanism.
