Abstract
High-strength Mg-Cu-Y amorphous alloys with significant supercooled liquid region have attracted attention as a structural light metal. The future application of the new alloys seems to be dependent on the development of a technique of consolidating the amorphous powders to an amorphous bulk. The effects of applied pressure, pressing temperature and flow strength of an alloy on the densification of amorphous powders by uniaxial warm pressing were examined for an amorphous Mg65Cu25Y10 alloy with a wide supercooled liquid region of 67K.
The amorphous alloy with a distinct glass transition phenomenon is easily consolidated near Tg, especially above Tg, and the minimum consolidation pressure required to obtain an amorphous bulk with true density is about four times as high as the flow strength of the alloy at the consolidation temperature. As the pressing temperature approaches Tg the effect of applied pressure on the densification decreases. The amorphous Mg65Cu25Y10 bulk with true density was obtained even at a small pressure of 0.2GPa, when the pressing temperature is 10K higher than Tg. The significant temperature dependence is attributed to the drastic decrease in the flow strength of the amorphous alloy by the glass transition.
