Evaluation of mechanical and electrochemical properties of laser surface modified Ti–6Al–4V for biomedical applications: in vitro study

Abstract

The effect of Nd:YAG laser surface modification on the microtopography and physicochemical properties of Ti–6Al–4V alloy has been investigated with a view of biomedical applications. The surface roughness and hardness of laser treated samples at 140 J cm⁻² were found to be 7±0·02 and 825 VHN respectively. The superior microhardness value can be attributed to grain refinement associated with laser melting and rapid solidification. The electrochemical property, mainly pitting corrosion resistance, has been carried out in Hank’s salt balanced physiological solution using standard potentiodynamic polarisation testing. A higher corrosion potential of −0·21 V was achieved for laser treated samples. At the optimum of laser fluence (140 J cm⁻²), energy dispersive X-ray analysis showed about a 30% decrease in vanadium content. Contact angle measurements also indicated improved surface wettability (i.e. hydrophilicity) characteristics at 35°. Finally, cell culture studies provided a useful tool to investigate the morphology and cell cytotoxicity of the laser treated surfaces.

Keywords:

• TI-6AL-4V ALLOY
• ND:YAG LASER
• CORROSION
• SURFACE MICROHARDNESS
• WETTABILITY