Characterization of Ti6Al4V powders produced by different methods for selective laser melting

Abstract

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.

Influence of Powder Production Process and Properties on Material Properties of Ti 6Al 4V Manufactured by L-PBF

“…The lower sphericity of powder B can be explained be the increased number of satellites, while for powder A both, distortion of particles and the rougher surface topology contribute to it. This is in contrast with Xie et al [4] who got similar sphericity for GA powder (0.94), but lowers for PA powders. (0.94 and even 0.87 for PS), which either indicates large difference in production patches or inability to make complete use of advantages of PA process.…”

“…However, also this measurements shows that powder A2 is rather similar to power B than A. This wider span for GA powder can also be found Bo Xie et al [4]. value for B/l3 of 0.94 due to the deformed particles and crates on the surface while plasma atomized powder C show the best result at 0.98 followed by A2 with 0.97.…”

“…This can be attributed to the higher overall oxygen level and exceeds even the tensile strength of highly oxidized powder by Williams et al [8], indicating that the dissolved Oxygen has more of an in uence than TiO 2 layers and particles, as found on powder B. This goes in perfect line with Xie et al [4], where also the powder with the higher oxygen content showed higher strength and less ductility, though not comparable in numbers since Grade 23 speci cation are different and samples were furnace annealed.…”

“…ASTM F3049 offers a standard for measuring properties with effect on additive manufacturing, but Sun et al [3] show for Grade 5 powder used for electron beam melting, which calls for a larger PDS from 50-100µm, that all properties, from PDS over sphericity to chemical composition greatly vary between different powder providers. Same is indicated by Xie et al [4] for titanium alloy Grade 23 and L-PFB, where powders from different providers and production processes show variation in particle size distribution, sphericity and achieved ductility.…”

Environmental Impact Assessment of Reconditioning Titanium Alloy Powder

“…A minimal amount of oxygen, hydrogen, and nitrogen must also be present in the metal [3]. As a result of these impurities, titanium will become hard and brittle, which may lead to cracks [4]. These contaminants are a by-product of the selective laser melting and atomization process exposing the material to air [5].…”