Chemical leaching of non-equilibrium Al(Ni-Fe) alloy powders produced by rod milling

In this paper, chemical leaching of non-equilibrium Al0.6(Ni0.5Fe0.5)0.4 powder by rod milling, is reported. X-ray diffractometry (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Mössbauer spectroscopy, and vibrating sample magnetometry (VSM) were used to characterize the rod-milled and leached specimens. After 200 h of milling, the AlNi bcc phase was detected in the XRD patterns. The crystallite size, calculated using Williamson–Hall and Scherrer methods, decreased rapidly for tm, less than 200 h, while the behavior of internal strain increases is the opposite. The leached specimens transformed to a ferromagnetic fcc Ni phase at above 400 °C of annealing for 1 h. The peak temperature and the width of DSC curves decreased with increasing leaching temperature. The relative intensity of the magnetic lines of sextet in Mössbauer spectra is reduced and the spectrum collapses into a distribution of doublet as the milling time increased. When the specimen cooled from 750 °C, the curve sharply increased to approximately 595, 580, and 542 °C for leached specimens in a 30 wt.% KOH solution at room temperature, at 55 and at 85 °C, respectively, indicating that the bcc phase has been transformed to a fcc phase.