The structure of the aluminium-abundant γ-brass-type Al8.6Mn4.4

Abstract

An aluminium-abundant Al8Mn5/γ-brass-type intermetallic with formula Al8.6Mn4.4, which is isotypic with γ-Al8Cr5 and γ-Al8V5, was discovered by high-temperature sintering of an Al/Mn mixture with initial composition Al2Mn. Structure analysis revealed that one special position (Wyckoff site 18h in space group R\overline{3}m) is shared by Al and Mn, with refined site occupancy factors of 0.7 and 0.3, respectively. The present low-temperature Al8Mn5-type phase crystallizes in the centrosymmetric space group R\overline{3}m (No. 166), rather than R3m (No. 160) as previously reported for the same intermetallic characterized by TEM measurements [Zeng et al. (2018). Acta Mater. 153, 364–376].