Physical characteristics of Ti-6A1-4V implants fabricated by electrodischarge compaction.

Physical characteristics of a Ti-6A1-4V implant were evaluated following fabrication using a new electrodischarge compaction technique. Ti-6A1-4V atomized powders were loaded into Pyrex tubes (3.3 mm ID) and subjected to a high-voltage, high-current-density pulse in air for a period of less than 300 microseconds. Single pulses (1.0, 1.5, 2.0 and 2.5 KJ/grampowder) were applied from a capacitor bank (240, 480 or 720 microF) to produce solid core implants with porous surface layers. Implants were evaluated microscopically for core size, neck size, pore size, grain structure, and incorporated oxide film. Hardness was also evaluated. Implants were compared with Ti-6A1-4V commercial powders. Core size increased and pore size decreased with increases in energy and capacitance. The cores were composed of equiaxed grains which were free of oxide at the grain boundary. Porous layers, consisting of particles connected in three dimensions by necks, were free of oxide films at the connecting interfaces. Neck size increased with increases in input energy and capacitance. Hardness readings of the core, necks, and porous particles resulted in readings higher than or similar to control materials. Electrodischarge compaction did not alter the physical characteristics during compaction.