Origin of the prepeak in the structure factors of liquid and amorphous Al-Fe-Ce alloys

Distinct prepeaks have been found in the structure factors of the liquid and amorphous Al-Fe-Ce alloys. The structural size of the chemical short-range order corresponding to the prepeak in the liquid alloy increases with decreasing temperature, and, after glass forming, the structural size is much bigger, and the amount of the structure corresponding to the prepeak increases with decreasing quenching temperature, but the structural unit size remains constant. The position of the prepeak shifts to smaller Q-values as the concentration of Ce increases. The addition of Ce can improve the interaction between atoms, so it is favourable to AI-based glass formability. The structural unit corresponding to the prepeak is an icosahedral quasicrystalline structure with Fe as the interstitial atom, and the prepeak is diffraction peak broadening caused by fairly fine (about 0.5-2.0 nm) icosahedral clusters.