In this study, pure Ti, Al, Dy powders were ball-milled with zirconia balls in argon atmosphere for 3 h at 800 rpm, producing a Ti- 6 wt.% Al- 4 wt.% Dy alloy powder. The alloy powder was consolidated by SPS technique at 1373 K for 15 min under 50 MPa pressure in vacuum. The sintered body had approximately 99% in density and 6 μm in grain size. XRD and TEM revealed the presence of the second phases such as Ti3Al, Al3Dy and Ti4Al20Dy phases, and their sizes were approximately 50 nm. Microhardness was approximately 960 Hv at room temperature, which decreased as temperature increased. However, there remained the micro-hardness significantly higher compared to the commercial Ti-6Al-4V alloy. After hardness test at 1173 K, XRD analysis did not show any difference in peaks, while the grain size and second phases size increased by ~4 μm and ~2 nm, respectively.

The effects of different types of balls on spark plasma sintering (SPS) characteristics of high energy ball milled Ti-48wt% Al-4wt% Nd powders were investigated. After ball milling with STS balls and zirconia balls at 800 rpm for 3 h in argon atmosphere, both powders showed shape factors of about 0.8, but their average powder sizes differed respectively at approximately 11 µm and 5 µm. From XRD results, only the peaks of pure Ti, Al and Nd were detected in both powders. The obtained Ti-Al-Nd powders were consolidated by SPS technique at 1373 K for 15 min under a pressure of 50 MPa in vacuum, resulting in high density over 99%. EDS and XRD analyses indicated the formation of binary phases such as TiAl3, TiAl, Ti3Al5, and NdAl3 after SPS in both cases of STS and zirconia balls, while the ternary Ti-Al-Nd phase was detected only in the case of zirconia balls. The size of second phases was slightly smaller in the case of zirconia balls. The microhardness of the sample was 790 Hv with zirconia balls and 540 Hv with STS balls.