Crystal structure determination of nanolaminated Ti5Al2C3 by combined techniques of XRPD, TEM and ab initio calculations

Crystal structure of Ti5Al2C3 was determined by means of X-ray powder diffraction (XRPD), transmission electron microscopy (TEM) and ab initio calculations. In contrast to the already known P63/mmc space group that the MAX phases crystallize, it was demonstrated that the $R\bar 3m$ space group could better satisfy the experimental data. The lattice parameters are a = 0.305 64 nm, c = 4.818 46 nm in a hexagonal unit cell.