Laser powder bed fusion (L-PBF) additive manufacturing processes require metal powder of a specific grain size. As this emerging technology becomes more established, demand for such material stock is increasing. Titanium is one of the most commonly used materials in metal additive manufacturing, used extensively for medical and aerospace applications because of its strength, light weight, and biocompatibility. As market demand grows, manufacturers are looking for options to secure an economical and reliable supply chain without sacrificing quality.
The standard techniques of fabricating titanium-6 aluminum-4 vanadium (Ti64) powder include the Plasma Atomization (PA) and Electrode Inert Gas Atomization (EIGA) methods. Although wire-fed plasma atomized powders have had the first-mover advantage on the market, recently, EIGA produced powders have been shown to be equivalent to PA powders for various physical and chemical properties. Last year Carpenter Additive released a white paper establishing the equivalency of these powder materials based on quantitative measurements of oxygen level, density, morphology, flowability, and contamination. To further these findings, we used both materials to build samples in order to compare the chemical, microstructural, and mechanical properties of finished additively manufactured Ti64 components produced from both EIGA and PA powders.
Test coupons were printed in varying orientations before being stress relieved and post-processed. For evaluation, the samples were subjected to uniaxial tensile, compression, Charpy, and fatigue testing, as well as microstructural, chemical, density, and porosity analysis. Printing was carried out by an independent third-party and all tests were conducted within the framework of ASTM F3001 and F3302 standards.
The results of the study on the printed parts demonstrated broad equivalency and consistency between the two powder types. EIGA powders, and thus components, contain less oxygen; while both EIGA and PA parts met ASTM F3001 compositional requirements, the lower oxygen levels in EIGA powders aid manufacturers’ powder re-use optimization strategies. The parts showed comparable tensile and compressive properties, while coupons printed from EIGA powders exhibited superior impact energy for enhanced microcrack resistance during additive builds. The results of both the comparative studies between EIGA and PA Ti64 establish EIGA powder to be a viable option to reduce costs while maintaining or improving the quality of printed parts.