Al-Fe-U (Aluminum-Iron-Uranium)

Ternary Phases 0 0 In the Fe-Al phase diagram [Massalski2], the solid solution c based on face-centered cubic (fcc) Fe is restricted by a loop. The solid solution based on the body-centered cubic (bcc) Fe (a) exists in both the disordered (A2) and the ordered (B2 and D0 1 -type ortho- rhombic). The Fe-U phase diagram [Massalski2] has two compounds: Fe 2 (orthorhombic) and Fe 3 -type cubic), there are three intermediate phases in the system with restricted ranges of homogeneity: FeAl 4 (monoclinic). In the Al-U system [Massalski2] , the intermediate phases are: UAl Liquidus Projection - The structural characteristics of seven known ternary phases of this system were summarized by [2006Rag]. All these phases are present in the isothermal section at 850 C [2005Gon]. In the Al-rich alloys reviewed here, UFe2Al10 (denoted s1 by [2006Rag]) (YbFe2Al10-type orthorhombic) is present. In addition, a new Al-rich compound U2FeAl20 (denoted s here) is present (not listed by [2006Rag]). This phase was reported by [2008Mes] to be tetragonal, space group I 42m with lattice parameters a = 1.24138 nm and c = 1.03014 nm. With starting metals of 99.99% Al, 99.99% Fe and 99.95% U, [2010Mes] arc-melted under Ar atm six ternary alloys containing 80 to 92 at.% Al. The phase equilibria were studied with differential scanning calorimetry, x-ray powder diffraction, optical and scanning electron microscopy and energy dispersive x-ray analysis. The liquidus surface constructed by [2010Mes] for Al-rich alloys is shown in Fig. 1. UFe2Al10s1 forms through the ternary peritectic reaction P1: L + UAl3 + Fe4Al13 $ s1 between 850 and 1157 C. U2FeAl20s forms through the reaction P2: L + U0:9Al4 s1 $ s at 639 C. Keeping in view the binary eutectic reactions at the Al-end in the Al-Fe and Al-U systems, the final solidification is tentatively shown in Fig. 1 as a ternary eutectic reaction E. (...truncated)