Synthesis of Al-Y-Ni-Co composites by mechanical alloying and consecutive spark-plasma sintering

The mechanical alloying process of Al85Y8Ni5CO2 under low-energy ball milling was studied. Atomic mixing ends after 100 h of mechanical alloying where the final product is a composite consisting of Al nanograins embedded in an amorphous matrix. Consolidation of the dry-milled powder was performed by means of spark-plasma sintering and yielded relative density of the sintered compacts of about 97%. The influence of liquid hydrocarbons impurities (saturated and aromatic) on the mechanical alloying process was investigated. A small additive of toluene (1 wt.%) to the initial mixture resulted in a considerable improvement of the structure of the mechanically alloyed powder, possibly due to the presence of carbon impurities. (C) 2009 Elsevier B.V. All rights reserved.