Structural modification of supersaturated BCC-Nd(Al) solid solution

The metastable Nd(Al) supersaturated solid solution with the BCC structure was synthesized by the melt-spinning method. The thermal stability of the supersaturated solid solution was studied by differential scanning calorimetry (DSC) and electrical-resistance measurements. The structural modification was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). A constrained BCC lattice was found due to the smaller Al atoms entering the BCC-Nd lattice. Two evident transformation stages were found during the heating process. The lower activation energy and negative temperature coefficient of the resistivity (TCR) suggest that a continuous structural transformation occur, which results from the softening mode of the highly metastable BCC structure. The strongly distorted and ultra-fine microstructure was observed directly by TEM