A ternary phase in Cu-Li-Mg system

Abstract

A previous study on CuLiMg system pointed out the existence of Cu8Li2Mg15, with an orthorhombic structure. The authors of the present paper also detected the existence of a ternary phase similar to the one mentioned. Due to some doubts on the phases structure, a study of CuLiMg was focused in an area near to the composition of that phase. SEM/EDS measurements of the phases compositions in equilibrium, as well as XRD powder patterns were obtained at room temperature. It was concluded that the ternary phase in CuLiMg system corresponds to CuMg2xLix (x0.11), with a hexagonal structure, space group P6222 (1 8 0), and lattice parameters a = b = 0.5260 nm, and c = 1.3649 nm. The structure was refined by Rietveld method; a Bragg reliability factor RB = 6.36% was obtained. Similarities between CuMg2xLix (x0.11) and NiMg2(H, D)x (x0.3) structures are detailed.