Effect of transition metals in the development of Al–Cu–Mg based metallic glass

Abstract

In the present study, the role of zinc, silver and nickel on the glass forming ability of a series of Al–Cu–Mg ternary alloys was investigated by both theoretical and experimental approach. The as cast structures and subsequent thermal stability of the amorphous alloys were investigated using scanning electron microscopy and differential scanning calorimetry. Based on atomic packing efficiency calculations, it was predicted that the base Al–Cu–Mg ternary alloys with the highest glass forming ability were those compositions located either near the ternary eutectic point or on the liquidus line of the liquidus projection. It was found that the substitution of Zn for Al in the ternary system coarsened the microstructure, while substituting Ag or Ni for Al or Cu respectively in specific Al–Cu–Mg alloys was found to refine the microstructure. The activation energy of primary crystallisation was found to be higher for the addition of Ni to the eutectic composition compared to the substitution of Ni for Cu in the eutectic Al–Cu–Mg ternary alloy.