Ab initio determination of atomic structure of Zn–Zr precipitates in a Mg–Nd–Zn–Zr alloy

The atomic structure of nanometre-sized Zn–Zr precipitates in a Mg alloy is determined by combining tilt series of micro-beam electron diffraction with atomic resolution Z-contrast imaging. The stoichiometry of the Zn–Zr precipitates is Zn₂Zr₃ with a primitive tetragonal structure (space group P4₂/mnm, a = b = 0.761 nm, c = 0.682 nm). There are 20 atoms in the unit cell of tetragonal Zn₂Zr₃, comprising 12 Zr atoms at the 4d, 4f, 4g positions and eight Zn atoms at the 8j positions.