A comparative investigation was made into Ti6Al4V powders produced by electrode induction melting gas atomization (EIGA), plasma spheroidization (PS), and plasma atomization (PA) in terms of particle size distribution, shape, element distribution, microstructure, flowability and forming properties. The powders were characterized by a laser particle size and shape analyzer, a scanning electron microscopy (SEM), an energy dispersive spectrometer (EDS), an x-ray diffraction (XRD), a Hall-flow meter and SLM machine, respectively. Image analysis was used to quantitatively analyze the elongation and roundness of these Ti6Al4V powders. The results indicate that PA produces the smoothest powder with the lowest satellite sphere. The microstructure of the powders is composed of HCP-α‘ phase. The average elongation and roundness of EIGA Ti6Al4V powder is similar to those of PA Ti6Al4V powder. The flowability of the PA powder (26.23 s/50 g) is better than that of EIGA powder (32.16 s/50 g) and PS powder (35.30 s/50 g). The SLM Ti6Al4V samples produced by EIGA powder exhibit a well-balanced combination of strength (1047 MPa) and ductility (16.2%). In regard to the process of SLM, the PA and EIGA Ti6Al4V powders are more suitable than PS Ti6Al4V powder. The EIGA method is found to be the best choice among these three methods on account of cost and performance.
This study employed TC4 rod as raw material to fabricate TC4 powders for laser 3D printing via electrode induction melting gas atomization (EIGA). The morphologies, phase compositions, particle size distributions, apparent densities and flowabilities of the powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPS) and Hall flowmeter, respectively. Moreover, the effects of gas atomization pressure and melting temperature on the yield of TC4 powders for laser 3D printing were studied. The results showed that TC4 powders morphology was nearly regular spherical. The particle size of TC4 powders showed a single peak normal distribution, mainly distributed in the range of 15−180 μm. The powder was α’−Ti of a single phase solid solution. The optimum parameters were gas atomization pressure of 5MPa, melting temperature of 1750°. Under the optimized condition, the average particle size D50 was 60.2 μm, the yield of printable TC4 powders was 35.6%, the flowability was 41.2 s/50g, the apparent density was 2.76 g/cm3 and oxygen content was 800 ppm, which was in line with the ASTM test standard and was conformed to the requirement for laser 3D printing.
Selective laser melting (SLM) currently uses the micro-fine spherical powder prepared by gas atomisation as a raw material. However, the spherical powder is expensive. In order to reduce the cost, this study first ball mills the pure titanium (CP-Ti) powder of hydrogenation-dehydrogenation (HDH). At a high speed and within a short period, the particle size distribution of the powder at a high rotation speed for 15 min is 12-45 μm with an angle of repose 34.3°. Then, the ball milling of titanium was mixed spherical powder with a wide grain size range up to 100 μm. This study presents the results of using SLM to produce CP-Ti parts starting from powder with mixed powder, in a different ratio between modified powder and spherical powder. The ultimate tensile strength (UTS) of SLM-parts of 8:2 ratio has been improved to 507 MPa, and the UTS of parts of 7:3 ratio has been improved to 522 MPa.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.