NANOSIZED FCC THALLIUM INCLUSIONS IN ALUMINUM

Ion implantation of pure aluminium with thallium induces the formation of nanosized crystalline inclusions of thallium with a f.c.c. structure. The size of the inclusions depends on the implantation conditions and subsequent annealing treatments, and is typically in the range from 1 to 10 nm. The inclusions are aligned topotactically with the aluminium matrix with a cube-cube orientation relationship, and they have a truncated octahedral shape bounded by {111} and {001} planes. The lattice parameter of the f.c.c. thallium inclusions is 0.484+/-0.002 nm, which is slightly but significantly larger than in the high-pressure f.c.c. thallium phase known to be stable above 3.8 GPa.