Preparation of bulk Ti-15Mo alloy using cryogenic milling and spark plasma sintering

Gas atomized Ti-15Mo alloy powder was processed by cryogenic milling. Both initial gas atomized and milled powders were consolidated by spark plasma sintering at temperatures ranging from 750 degrees C to 850 degrees C for 1 and 3 min. Microstructure of the sintered samples was studied by scanning electron microscopy (SEM), chemical contamination was determined by carrier gas hot extraction (CGHE) method and phase composition was investigated by X-ray diffraction. Cryogenic milling resulted in severe plastic deformation of initially spherical particles, changing their shape, but without a significant decrease of particle size. The milled powder achieved the full density after sintering at 750 degrees C, while 850 degrees C was required for a full densification of the initial powder. The amount of a phase was higher in the sintered milled powder, while the sintered non-milled powder contained significant amount of (a phase. It was shown that an ultrafine-grained two-phase microstructure can be produced by a combination of cryogenic milling and spark plasma sintering.