Effect of ball milling parameters on the microstructure of W-Y powders and sintered samples

High energy milling carried out in a planetary ball mill was used in order to alloy elemental powders and to obtain nanostructures and oxide dispersion strengthened (ODS) alloys. Owing to such advantages, this process was retained so as to elaborate ODS tungsten alloys from tungsten and yttrium powders by using a WC-Co milling system with 16 balls. The experiments were performed for a duration of up to three days while applying a 400 rpm speed and a ball-to-powder weight ratio of 16. The W-1 vol%Y blends were subsequently compacted at room temperature and sintered at 1800degreesC for 4 h. The present paper deals with the effect of milling time on the mechanical behavior of the powders, on the refinement of the microstructure, on the improvement of the second phases distribution and on the contamination by cobalt, carbon and oxygen. At last, these results are related with the behavior of the powders during densification. (C) 2003 Elsevier Ltd. All rights reserved.