Influence of different solution media on microstructure and mechanical properties of porous titanium

The porous titanium (PT) with porosity of 45% was fabricated by a stacked-forced-sintering method. The specimen was treated by three solution media, which were a mixture acid (HF: HNO_3:H₂O=5:15:80) medium (ACT), alkali medium (5 mol/L NaOH, 24 h) and heat treatment (630℃/1 h) abbreviated as AKT, as well as simulated body fluids treatment (SBF). The microstructure and mechanical properties of the treated and untreated (UT) specimen were investigated by scanning electron microscope (SEM), elements analysis (EDS), X-ray diffraction analysis (XRD) and universal testing machine. The Young's modulus and yield stress (σ_0.2) were calculated from the stress-strain curve. The results show that the surface of porous titanium treated by ACT is smooth and lamellar, while the surface treated by AKT is porous with nano/mirco-pore. And the uniformly hydroxyapatite have been observed on the surface of the specimen treated by SBF. Young's modulus of PT treated by ACT and AKT are dramatically declined, but Young's modulus of of PT treated by SBF increases on the contrary. The yield stress has the same tendency, but it is not changed so sharply as Young's modulus.