Comparison of spark plasma sintering of elemental and master alloy powder mixes and prealloyed Ti-6Al-4V powder

Spark plasma sintering (SPS) has been used to fabricate Ti-6Al-4V * from elemental titanium and 60Al-40V master alloy powder mixes (EM powder mixes) and prealloyed (PA) Ti-6Al-4V powder. The use of EM powder mixes resulted in rapid near-pore-free densification (5 min at ≥900°C under 30 MPa) and noticeably higher yield strength (YS) and tensile elongation than did the use of PA powder. In addition, the homogenization of vanadium in Ti-6Al-4V was accelerated significantly by SPS (completed in 15 min at 1,100°C under 30 MPa). Also, unlike conventional powder metallurgy (PM), the sintered density was essentially independent of the titanium powder size and master alloy powder size in SPS. Densification occurs primarily by plastic deformation of the titanium powder particles. SPS is effective in consolidating Ti-6Al-4V from EM powder mixes and produces excellent tensile properties (UTS = 1,037 MPa, YS = 929 MPa, elongation = 22%)