Production of spherical titanium alloy powders used in additive manufacturing from titanium scrap

Abstract

The main materials for 3D printing of titanium are fine metal alloy powders from which produce final articles with required quality. These powders must have definite chemical compositions, physical/mechanical characteristics, and also necessary operational properties. Key parameters of titanium alloy powders are homogeneity of chemical compositions, microstructures as well as flow ability. Conventional atomisation methods for metal powders like GA, PREP, PA, etc, are complicated and sufficiently expensive. Alternative production route is usage of complex processing technology of titanium alloy scrap as initial raw material. Spheriodised powder manufacturing scheme which includes raw material preparation, preliminary and final treatments have been presented. At the first step titanium scrap was divided according to titanium alloy types, purified from contaminants and oxide films. Then prepared materials were converted to non-spherical powders with definite fractional compositions using hydrogenation/de-hydrogenation (HDH) method. Experimental HDH equipment allows close cycle of hydrogen recovery almost without losses. Obtained non-spherical powders were treated in the plasma unit yielding spherical titanium alloy. Offered technical solutions permit production of raw materials for 3D printing from scrap with high actual yield of required fractional compositions.