Synthesis of the magnesium-based nano/amorphous-composite alloy powder by the combination method of melt-spinning and mechanical alloying

A series of Mg-based alloys with composition of Mg₆₅Y ₁₀Cu_25-xAgx, x = 0, 5, 10, were selected for investigating the microstructure evolution of the Mg-based nano/amorphous-composite alloy powder synthesized by the combination method of melt-spinning and mechanical alloying (MA). The microstructure characterization of the alloy powders was conducted by means of DSC, XRD, FEG-SEM, and TEM techniques. The result of XRD reveals that the entire as-quenched alloy ribbons exhibit a broaden diffraction pattern of amorphous phase. After 50 hours milling the mixture of amorphous alloy ribbons with 5 vol.% of nano-sized ZrO₂ by planetary mill, the ZrO₂ dispersed magnesium composite alloy powder can reach to a homogeneous size distribution. In parallel, the MA composite Mg-based alloy powders still remain an amorphous state by the characterization of X-ray diffraction and the DSC analysis. A clear Tg (glass transition temperature) and most wide supercooled region (about 44 K) were revealed for both the Mg ₆₅Y₁₀Cu₂₀Ag₅ alloy ribbon and the MA magnesium composite powder. In addition, the result of TEM observation also revealed that the ZrO₂ with average particle size of 80 nm distributed homogeneously in the amorphous matrix of the Mg₆₅Y ₁₀Cu₂₀Ags /5 vol.% ZrO₂ composite alloy powder. The interface between the ZrO₂ dispersoid and the amorphous matrix of the composite alloy powder exhibits a very good bonding condition.