A new descendant of the γ-brass family in the zinc rich Ni-Zn-In system

Abstract

Abstract The first ternary intermetallic phase - Ni11.4+xZn19.8In14.9-y (0\u202f≤\u202fx\u202f≤\u202f0.2; 0\u202f≤\u202fy\u202f≤\u202f0.1) in the Ni-Zn-In system is presented. The structure of the phase has been analysed by single crystal X-ray diffraction. Due to the similar X-ray scattering factors for Ni and Zn, a combination of X-ray and neutron diffraction has been employed to identify accurate sites of Ni and Zn in the structure of the Ni-Zn-In phase. The phase is structurally complex and adopts a narrow homogeneity range. The structure crystallizes in the orthorhombic space group Cmcm (63) and contains 46 atoms per unit cell which bears all types of disorder phenomena (vacancies, mixed site occupancies, and positional disorders) that is typical for complex metallic alloys. The structure is mostly tetrahedrally close-packed and is generated mainly by two types of endohedral clusters: a 12-atom cluster that is closely related to an icosahedron and an 11-atom polyhedron that is related to twinned cuboctahedron. The phase is stabilized at valance electron concentration between 1.82 and 1.83 e/a.