Enhanced thermal stability of amorphous Al-Fe alloys by addition of Ce and Mn

Abstract The thermal stability of mechanically alloyed amorphous Al-Fe-based alloy powders, with nominal compositions Al 82 Fe 16 Ce 2 and Al 82 Fe 14 Mn 2 Ce 2 , was investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM) complemented by energy-dispersive x-ray spectroscopy (EDX). Analysis through DSC indicated that both Al 82 Fe 16 Ce 2 and Al 82 Fe 14 Mn 2 Ce 2 alloys undergo a two-stage crystallization process. Notably, the initial crystallization temperatures for the Al 82 Fe 16 Ce 2 and Al 82 Fe 14 Mn 2 Ce 2 alloys were determined to be approximately 525 °C and 550 °C, respectively. This high thermal stability is attributed to the delayed nucleation process induced by the presence of Ce and Mn within the Al-Fe matrix. During polymorphic crystallization, distinct phases such as β -AlFe, Al 13 Fe 4 for Al 82 Fe 16 Ce 2 , and β -Al(Fe, Mn), Al 13 Fe 4 , Al 10 CeMn 2 for Al 82 Fe 14 Mn 2 Ce 2 were identified. Furthermore, post-annealing of these amorphous alloy powders at elevated temperatures of 600, 700, and 800 °C led to distinct morphological characteristics based on the alloy composition. For Al 82 Fe 16 Ce 2 , the particles preserved a nearly spherical morphology, with size distributions ranging from 1 to 5 μ m. In contrast, for Al 82 Fe 14 Mn 2 Ce 2 , the particles exhibited an irregular shape with a broader size range of 1 to 15 μ m.