Abstract
The present study has investigated the influence of calcium process control agent on the microstructure and mechanical properties of powder metallurgy processed samples fabricated by milling and spark plasma sintering technique. The microstructure of spark plasma sintered Ti-6Al-4V with 0.3 wt% Ca (Ti-6Al-4V-0.3Ca-M) samples revealed fine grain structure compared to sintered unmilled (Ti-6Al-4V-UM) samples. The average grain size values of sintered Ti-6Al-4V-0.3Ca-M and Ti-6Al-4V-UM samples are 8 and 60 mu m, respectively. The spark plasma sintered Ti-6Al-4V-UM exhibited a yield strength (YS) of 875 +/- 10 MPa, ultimate tensile strength (UTS) of 1057 +/- 2 MPa, and % elongation (% El) of 15 +/- 2. The spark plasma sintered Ti-6Al-4V-0.3Ca-M exhibited higher YS of 964 +/- 9 MPa, UTS of 1153 +/- 7 MPa, and lower % El of 6 +/- 1 when compared to mill annealed Ti-6Al-4V alloy (YS 899 MPa, UTS 978 MPa and %El 15). The higher strength of Ti-6Al-4V-0.3Ca-M sintered samples could be attributed to the fine grain structure and the presence of interstitial elements in the matrix. In contrast, the lower strength of Ti-6Al-4V-UM can be ascribed to its coarse grains.