Metastable phase formation with dendrite growth during laser-induced rapid solidification of Al₅₉Ge₄₁ sputtered thin films

In the present work rapid solidification processes in amorphous Al59Ge41 thin films are induced by means of laser irradiation and within a wide range of pulse durations (50 μs - 500 ms). Results show that the metastable eutectic structure, formed by alternating lamellae of a hexagonal metastable phase and textured aluminium crystals, grows over a wide cooling rate interval. In the regime of millisecond pulses, additional aluminium dendrites, nucleated at germanium crystallites, are formed and allow us to conclude that this metastable hexagonal phase is favoured by small undercoolings. © 1988.