Investigation on Fabrication and Microstructure of Ti–6Al–4V Alloy Hollow Spheres by Powder Metallurgy

In this study, the Ti–6Al–4V alloy hollow spheres were prepared by powder metallurgy method under different sintering temperatures (1200 °C, 1250 °C, 1300 °C, 1350 °C and 1400 °C). And the density, shrinkage and microstructure of hollow spheres were tested by Archimedes drainage method, diameter measurement, optical microscope and scanning electron microscope, respectively. The results show that the density and shrinkage of hollow spheres increase gradually with the sintering temperature increasing, while the porosity of the shell of hollow spheres decreased along with the increase of sintering temperature. When the sintering temperature is 1400 °C, the hollow sphere has the largest density of 2.10 g/cm³, the largest shrinkage of 22.0% and the smallest porosity of 14.2%. By comparing the micro-morphology and properties under different temperatures, when the sintering process lasted for 180 min at 1400 °C, the Ti–6Al–4V hollow spheres have the smallest porosity and the largest density.