Bulk Amorphous Samples from Al-Mm-Ni System

Abstract

Recent studies have shown that bulk amorphous alloys from Al-basedternary systems, containing lanthanide metal and late transition metalcan be fabricated. Such materials are characterized by good mechanicalproperties. The most common production method of these alloys is meltspinning, giving a ribbon as a final product. In order to reduce thecost of material it is possible to replace lanthanide metal bymischmetal (Mm), which is one order of magnitude cheaper than purelanthanides. The mischmetal used in this study contains {[}in at.%]:Ce-50.3, La-43.5, Pr-5.9, Nd-0.3. This study had two main objectives.First - to check the possibility of replacement of yttrium in theAl-Y-Ni system alloys by mischmetal, without losing the structure andmechanical properties. The other goal was to produce the bulk amorphousmaterial. Five alloys from Al-Mm-Ni system were investigated. Theas-quenched ribbons were milled to powder and then semi-isostaticallycompacted at elevated temperature to bulk material. After every step ofthe investigation, the XRD and DSC measurements were performed todetect possible changes of structure occurring during each step of theprocess: ribbon production, milling, compaction. Mechanical propertieswere characterized by Vickers microhardness. The results of the studiesshow the possibility to produce bulk amorphous alloys of the abovementioned system in three-step production cycle. The microhardness isgood or even better compared to Al-RE-Ni alloys. The microhardnessdepends not only on the chemical composition of the alloy but also onthe temperature of the compaction process.