Phase relations and hydrogenation behavior of Sr1−xCaxAl2 (0≤x≤1)

Thermodynamics and Constitution of Mg-Al-Ca-Sr-Mn Alloys: Part I. Experimental Investigation and Thermodynamic Modeling of Subsystems Mg-Ca-Sr and Al-Ca-Sr

“…Superimposed are the compositions of the three present samples (solid dots) and the results of the phase analysis with EPMA from this work and by XRD from Ref 5. The huge ternary solubility of the C15-Al 2 Ca phase is remarkable, extending almost to the binary Al-Sr edge and leaving only 10 wt.% Ca in C15. This incident and the narrow gap to the Al 2 Sr phase was found by Zhang et al [5] with XRD and is well supported by the present findings with EPMA. Only the combination of the results from XRD and EPMA enable a clear identification of this most Sr-rich phase composition and a distinction between the Al 2 Sr and the C15 phase.…”

“…No data could be found in the literature for the ternary Mg-Ca-Sr system, and only one study relates to the Al-Ca-Sr system. Zhang et al [5] investigated six alloys in the section Sr 1Àx Ca x Al 2 (0 £ x £ 1) with x-ray diffraction (XRD). Their main interest was in the hydrogenation behavior of these alloys, but they also characterized the alloys before exposure to hydrogen.…”

“…They converted existing thermodynamic descriptions to the modified quasi-chemical model in a reoptimization of the binary subsystems. No ternary solubilities of the binary phases were considered in that work; specifically, the only experimental work in that system, revealing extended solutions on the Al 2 Ca-Al 2 Sr section, [5] was not considered.…”

Crystal structure of a new compound (Sr0.47Ca0.53)2Al

“…However, the structures of their aluminides, except for CaAl 4 and SrAl 4 , are quite different. The structural difference may be related to the atomic sizes of Ca and Sr. For example, Sr 1 − x Ca x Al 2 crystallizes with an orthorhombic structure in space group Imma when x ≤ 0.1, but with a cubic structure in space group Fd-3m when x ≥ 0.3 [9].…”

Crystal structures and hydrogenation characteristics of Ca8(Al1−xNix)3 alloys

“…However, both CaAl 4 and CaAl 2 cannot absorb hydrogen [6], which may be related to their structures. Thus it is necessary to understand whether Ca 8 Al 3 can react with hydrogen.…”