Effect of friction hardening pre-treatment on increasing cytocompatibility of alkali heat-treated Ti-6Al-4V alloy

Alkali heat treatment (AHT) has been widely used as an effective surface chemical modification to improve the bioactivity and biocompatibility of titanium and its alloys; however, this method suffers from long process time. In this study, friction hardening (FH) as a cost-effective and straightforward severe plastic deformation (SPD) technique prior to AHT was applied in order to reduce the time-consumption and the manufacturing costs of AHT method. The results showed that the chemically modified FHed (FAHT) samples could prepare finer hierarchical nano/meso-structured network, with an average size range of 20-130"¯nm, on the surface of Ti-6Al-4V alloy at significant lower treating time. According to XPS results, this surface nanostructure possessed the toxic-element-free oxide layers. In-vitro cell culture showed that FAHT substrates, especially FAHT600-12 sample could remarkably enhance the cell-substrate interactions including: cell adhesion, spreading, proliferation as well as ALP activity. This can be attributed to both finer topography and better wettability.