Dissolution and precipitation under gravitational conditions in the W–Al system

Metallurgical Preparation of Nb–Al and W–Al Intermetallic Compounds and Characterization of Their Microstructure and Phase Transformations by DTA Technique

“…Vacuum induction furnaces usually do not reach temperatures suitable for the melting of refractory metals; however, due to the high reactivity of melted Al, it is theoretically possible to prepare W-Al alloys by this method if the charge is optimised and the furnace and crucible are allowed longer stabilization times around temperatures 1600 • C and higher. Frkanova and Lapin [14] reported that it is possible to produce alloys with a composition of 14 at.% Ta and 86 at.% Al by vacuum induction melting in an Al 2 O 3 -based crucible with a stabilization time from 60-270 s at a temperature of about 1600 • C. The significant dissolution of W in the Al melt was also reported by Unuvar [11,12] during self-propagating high-temperature synthesis (SHS) at 1600 • C.…”

“…However, the low solubility of W in Al and the large difference between melting temperatures of W and Al make it difficult to fabricate W-Al intermetallic compounds. There are very few publications dealing with the preparation and properties of intermetallics based on W-Al, and powders are generally used as input materials, with subsequent processing by mechanical alloying, self-propagating high-temperature synthesis (SHS), or both [9][10][11][12]. Only limited information on the preparation of Nb-Al and W-Al alloys by conventional metallurgical methods is available.…”