Fabrication of spherical Ti–6Al–4V powder for additive manufacturing by radio frequency plasma spheroidization and deoxidation using calcium

Abstract

Commercial hydride-dehydride Ti–6Al–4V powder was used as raw material to fabricate high-quality spherical Ti–6Al–4V powder by radio frequency (RF) plasma spheroidization and calcium deoxidation in this work. The spheroidized and deoxidized Ti–6Al–4V powder were examined by X-ray diffraction, scanning electron microscopy and O/N/H analyzer, respectively. Effects of feeding rate on spheroidization of Ti–6Al–4V powder were investigated. Effects of calcium reduction on microstructure and oxygen content of spheroidized Ti–6Al–4V powder was also studied. Results show that better flowability of 28.01 s/50 g and higher apparent density of 2.43 g/cm3 can be obtained when feeding rate is 80 g/min. However, the appropriate feeding rate for higher spheroidization ratio and lower mass loss ratio is 140 g/min. Oxygen content of Ti–6Al–4V powder can be reduced to 1240 ppm by deoxidation without phase transformation.

Keywords

• Radio frequency plasma
• Spheroidization
• Ti–6Al–4V powder
• Spherical powder
• Deoxidation