Crystallization of Al-Mg-Ce and Al-Mg-Ni-Ce amorphous alloys

摘要

The crystallization behaviors of Al_(82)Mg_(10)Ce_8, Al_(84)Mg_(10)Ce_6, Al_(82)Mg_6Ni_4Ce_8, Al_(84)Mg_7Ni_3Ce_6 and Al_(84)Mg_8Ni_2Ce_6 amorphous alloys have been studied by different scanning calorimetry (DSC) and X-ray diffraction. Al_(82)Mg_(10)Ce_8 and Al_(84)Mg_(10)Ce_6 amorphous alloys are characteristic of an interesting crystallization behavior. A non-equilibrium phase Al_(92)Ce_8 precipitates in the first stage crystallization as primary phase. In the subsequent crystallization stage, Al92Ce8 phase decomposes into fcc-Al and Al_4Ce phases, at the same time, Al_(12)Mg_(17) phase precipitates. Strikingly, a small Ni addition can promote the primary crystallization of fcc-Al, as example obtained in Al_(82)Mg_6Ni_4Ce_8, Al_(84)Mg_7Ni_3Ce_6 and Al_(84)Mg_8Ni_2Ce_6 amorphous alloys. This interesting crystallization mechanism can be well interpreted in terms of the heat of mixing.