High-temperature ball milling: An efficient method to fabricate Ti and its alloy powder for additive manufacturing

The low cost effectiveness of spherical titanium and its alloys powder for additive manufacturing (AM) has been widely concerned. This study proposed high-temperature ball milling (HTBM) to modify irregular titanium and its alloys powder for AM, such as hydrogenation-dehydrogenated titanium (HDH Ti), and the ball milling mechanism was revealed. The results showed the irregular HDH Ti powder gradually turning into nearly spherical and flake structures. The modified Ti powder flowability exhibited a mass flow rate of 46.1 +/- 0.3 s/50 g, an angle of repose (AOR) of 35.5 +/- 0.5 degrees and an oxygen increment of only 300 ppm with a BM T of 490 celcius, a BM t of 14.1 h and a B/M ratio of 2:1, which met the AM requirements. There were continuous fish scale-shaped single and multiple tracks, and complex demonstrative parts were successfully manufactured via selective laser melting using modified powder. The theoretical analysis of the normalized average deformation (U) revealed that the modified powder for AM needed meet two requirements: (1) U was over 16.7 % and less than 51.5 %, and (2) the total collision number was lower than 1.2 x 107. Overall, this study offers a method to apply irregular Ti and its alloys powder for AM. (c) 2024 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.