Tohru Kohno

New gas atomizing technique for Nb{sub 3}Al intermetallic alloy

Plasma-Melt-Gas-Atomizing (PMGA) technique has been developed to produce rapidly solidified powders of intermetallic alloys for ultra-high temperature structural applications. Using this technique, rapidly solidified Nb{sub 3}Al powders have been produced. These powders consist mainly of supersaturated solid solution of Al in Nb (A2), while the conventional cast structure consists of ordered A 15, and may be a good source for most powder metallurgical applications. Furthermore, a unique technique to control the powder size distribution is currently under development. In-situ measurement method of the atomized powder size distribution has been examined by using phase Doppler particle analyzer to control final powder size distribution by the feedback from the in-situ measurement data to the control system of the Plasma-Melt-Gas-Atomizer.