Heat treatment effect on the mechanical properties, roughness and bone ingrowth capacity of 3D printing porous titanium alloy

The weak mechanical strength and biological inertia of Ti–6Al–4V porous titanium alloy limit its clinical application in the field of orthopedics. The present study investigated the influence of different solution temperatures (e.g. 800 °C, 950 °C and 1000 °C) on the mechanical properties, roughness and bone ingrowth capacity of Ti–6Al–4V porous titanium alloy prepared by Electron Beam Melting. It was found that the compressive and shear strength were promoted with the increase of solution temperature because of the transformed crystallinity of Ti–6Al–4V titanium alloy and phase changes from TiAl to TiAl + TiV. In addition, the topological morphology, surface roughness and wettability of the porous titanium alloy scaffolds were improved after heat treatment, and in turn, the adhesion rate and cell proliferation of bone marrow mesenchymal stem cells were enhanced. Compared with the scaffolds before and after heat treatment at 800 °C, the scaffolds heat-treated at 950 °C and 1000 °C achieved better bone ingrowth, extracellular matrix deposition and osseointegration. These findings indicate the great potential of heat treatment in possessing Ti–6Al–4V porous titanium alloy for orthopedic implant.