Study of crystallization mechanism of Al-based amorphous alloys by in-situ high temperature X-ray diffraction method

The role of transition metals (TMs) addition on the formation and crystallization of amorphous Al(85)TMs(10)Y(5) alloys was described using in-situ high-temperature X-ray diffraction. The structural results were compared with differential scanning calorimetry and dynamical mechanical analysis to obtain detailed information about the nucleation and growth of crystalline phases. The performed analysis confirmed that Fe and Cu addition drastically changes the crystallization temperature and the phase composition of the fully crystallized alloys. While for Al(85)Ni(10)Y(5) alloy, the second crystallization step is related to the formation of Al(19)Ni(5)Y(3) phase, for Al(85)(Ni, Fe)(10)Y(5) and Al(85)(Ni, Fe, Cu)(10)Y(5) alloys crystallization of Al(15)Fe(9)Y(2) phase was observed. Interestingly, the performed analysis showed that forming a homogenous amorphous phase is not necessary to obtain the best corrosion resistance. It was noted that the precipitation of the YCr(2)Al(20) phase in the Cu-rich amorphous matrix should be a much more interesting approach.