Fabrication of fully porous and porous-surfaced Ti-6Al-4V implants by electro-discharge-sintering of spherical Ti-6Al-4V powders in an one-step process

A single pulse of 0.75–2.0 kJ/0.7g-atomized spherical Ti-6Al-4V powder in two size ranges (100–150 and 150–200 μm), using 150, 300, and 450 μF capacitors, was applied to produce fully porous and porous-surfaced implant compacts. The solid core formed in the center of the compact after discharge was composed of acicular α + β grains and a porous layer consisting of particles connected in three dimensions by necks. Capacitance and input energy are the only controllable discharge parameters even though the heat generated during a discharge is the unique parameter that determines the porosity of the compact. It was shown that electro-discharge-sintering of spherical Ti-6Al-4V powders can efficiently produce fully-porous and porous-surfaced Ti-6Al-4V implants with various porosities in short times (<155 μs) by manipulating the discharge condition such as input energy and capacitance including powder size.