Effect of Post Heat Treatment on the Mechanical Properties of Porous Ti–6Al–4V Alloys Manufactured through Powder Bed Fusion Process

Abstract

Ti-6Al-4V alloys are widely used as a structural material. Open-cell porous Ti-6Al-4V alloys with different porosities are manufactured through powder bed fusion process. Cylindrical specimens consisting of ordered truncated octahedron unit-cells are designed using a 3D-CAD software. After the building, porous Ti-6Al-4V alloy specimens are annealed at different temperatures of 1173 and 1323K for 1 h in vacuum. Vickers hardness of the annealed specimens is lower than those of as-built specimens. This is due to the increased volume fraction of beta phase which is measured by SEM observation and X-ray diffraction analysis. On the other hand, initial peak stress and energy absorption increase after the annealing because of the enhanced ductility of cell edges. Most specimens show the macroscopic shear band formation during compression tests, which causes the reduction of energy absorption. The ordered cell structure which is one of the reasons of the shear band formation is not suitable for energy absorbing applications.