SPRAY ATOMIZATION AND DEPOSITION OF TANTALUM ALLOYS

A Ta-Fe alloy was atomized and spray-deposited. The spray deposition p rocess was investigated experimentally and numerically. An induction s kull melting (ISM) spray forming process was used. The spray formed ma terials and oversprayed powders were characterized using optical micro scopy, X-ray diffraction and scanning electron microscopy. A theoretic al and numerical analysis was undertaken in order to gain some insight concerning the spray deposition of tantalum and complement the experi mental data where measurements were impractical. These simulations are based on a previously developed multi-directional solidification mode l combined with a Navier-Stokes solver for flows with interfaces. Vari ous droplet size and impact velocities consistent with the experiments were considered. The results show that liquid-jet overflow occurs onl y for droplets with a diameter larger than the mean size. Comparisons of the measured and calculated final splat sizes show that the numeric al model gives a good estimate of the final droplet spreading behavior . (C) 1997 Acta Metallurgica Inc.