Synthesis of NiTi alloy powders for powder-based additive manufacturing

Abstract

Spherical powders of NiTi intermetallic compound were obtained from elemental powders by mechanical alloying at various modes followed by plasma spheroidization. The obtained powders were analyzed in terms of its chemical composition, sizes, morphology and microstructure. The plasma spheroidized NiTi powder was found to contain from 5.5% to 8.7% of the Ti2Ni phase in the form of a dendritic structure. It was also found that an increase in the mechanical alloying time leads to a more uniform distribution of elements in the powder, however, it significantly increases the iron impurity originating from the grinding of steel balls. Furthermore, granulometric composition of the synthesized powders was observed to depend on the size of the initial particles before spheroidization.