Microstructural development and mechanical properties of drop tube atomized Al-2.85 wt% Fe

Partitionless solidification and anomalous triradiate crystal formation in drop-tube processed Al-3.9 wt%Fe alloys

“…Moreover, some samples also show regions displaying the growth of primary dendritic α-Al. Based upon the metastable phase diagram proposed in our previous work [15], Al-3.9 wt% Fe misses the coupled zone for the Al-Al13Fe4 eutectic in favour of primary α-Al growth if a minimum of undercooling of 110 K is attained. In addition, much of the sample is occupied by eutectic, this being both the stable Al-Al13Fe4 lamellar eutectic and the metastable Al-Al6Fe rod-like eutectic.…”

“…Figure 4d shows that both rod-like and lamellar eutectic with different sizes and densities are present in the sample, and that these eutectics are divided by a distinct boundary. Our previous research [15] has shown that while the lamellar eutectic is Al-Al13Fe4, metastable Al-Al6Fe eutectic adopts a rod-like structure. That is, both stable Al-Al13Fe4 and metastable Al-Al6Fe eutectics are formed in the slowest cooled sample.…”

“…However, the cooling rate can be estimated using the heat balance of the solidifying droplets. The method for the estimation of the cooling rate is given elsewhere [15]. Figure 1 gives the cooling rates of the droplets as a function of their diameter.…”

“…It is likely this is because the Al-Al13Fe4 eutectic coupled zone, which is heavily skewed towards the intermetallic side, can be by-passed via deep undercooling. A recent re-evaluation of the Al-Al13Fe4 coupled zone is presented in [15]. Electromagnetic levitation (EML) studies [7] on the Al-8 wt% Fe alloy have shown the formation of what the authors describe as primary star-like Al13Fe4, together with the formation of metastable Al-AlmFe and Al-AlxFe (x = 5) eutectics beyond an undercooling of 155 K.…”

Rapid solidification of AlCoCrFeNi2.1 High-entropy Alloy

“…As such, for gas atomization, cooling rates obtained using a heat balance equation (such as shown in Equation 1) would not necessarily be expected to show strong agreement with cooling rates calculated by measurements of secondary dendrite arm spacing (SDAS). In contrast, drop tube studies have shown strong agreement between cooling rates inferred from SDAS measurements and those obtained via Equation 1one such agreement was recently shown in drop tube processed Al-2.85 wt% Fe [26].…”