Fig. 1. SEM-SE images of high-energy ball-milled powder of (a) Al-2V, (b) Al-5V, and (c) Al-10V alloys with the particle size distribution graph at the bottom.

Fig. 2. XRD profiles of (a) Al-2V, (b) Al-5V, and (c) Al-10V showing the shift in peaks and formation of intermetallic as a function of SPS temperature. The dotted lines represent the position of the peak for pure Al and Al3V for reference to observe the peak shift.

Fig. 3. (a) Grain size, and (b) solid solubility of V in Al as a function of SPS temperature. Data for the cold compacted alloy is alloy is also included for comparison.

Fig. 4. BSE images of Al-2V (a-d), Al-5V (e-h), and Al-10V (i-l) after high-energy ball milling and consolidation at room temperature (CC) and SPS at 200, 250, 300, and 400 °C, respectively. 3 GPa pressure was applied for cold compaction. 1 GPa pressure was used for SPS at 200, 250, and 300 °C, while 600 MPa was used at 400 °C. High magnification images are shown as an inset on the top-right corner. The dark phase, bright steak-type phase, inter-particle boundaries, and inter-particle pores are indicated by yellow, purple, green, and orange arrows, respectively. Unalloyed V particles and abraded stainless steel particles are denoted by the dark red dotted circle and cyan arrow, respectively.

Fig. 5. EDXS area maps of Al and V for Al-10V SPSed at 400 °C. Red dotted lines show the V-lean phase; green dotted lines indicate the segregation of V (V-rich phase) along the inter-particle boundary.

Fig. 6. HAADF image and STEM-EDXS area maps for cold compacted Al-10V alloy showing fine V-rich regions in the alloy.

Fig. 7. (a) STEM-BF image of Al-10V alloy (SPSed at 400 °C) showing regions with fine grains (and V-rich) and coarse grains (V-lean). (b) High-resolution HAADF image and EDXS area maps for V, Al, and O. The yellow circles in V-EDXS area maps represent the V-rich phase along the V-rich and V-lean interface, (c) HAADF-STEM image showing the fine bright particles of Al3V at the vicinity of the V-lean phase, (d) HAADF-STEM image showing the combination of bright particles and network structure of V (e) HAADF-STEM image taken far from the V-lean phase (i.e., close to particle center) showing the network structure of V.

Fig. 8. Schematic diagram to illustrate the consolidation of HEBM powder particles and the microstructural evolution occurring during the SPS process.