Real time study of the growth of i-AlCuFe in very thin films obtained by simultaneous deposition of the components

To study the physico-chemical properties of i-AlCuFe alloys in the form of very thin films, it is necessary to use films with a smooth free surface, good quasicrystalline quality (without crystalline phases) and without porosity. The best film quality (smooth and homogeneous) was obtained by simultaneous deposition of three elements. The amorphous deposit is then annealed. To optimize this annealing treatment, the crystallization of the deposit was observed. Several TEM grids were overlaid during the same deposition. Each grid was heated up to a different temperature threshold in the range of 350–600 °C and observed in real time by TEM. From these measures we observe that the quasicrystalline transformation of these ‘amorphous’ alloys begins with a primary crystallization where the β Al50(Cu,Fe)50 crystalline phase and α-Al precipitates appear in a residual ‘amorphous’ matrix. The radius of these β particles increases as t1/3, where t is the annealing time. Only above 450 °C are nucleation and growth of i-AlCuFe observed. This growth occurs around the β grains. The radius of i-AlCuFe grains also increases as t1/3, thermally activated with an activation energy equal to 110 kJ/mol.