A COMPARISON OF THE SINTERING CHARACTERISTICS OF BALL-MILLED AND ATTRITOR-MILLED W-NI-FE HEAVY ALLOY

Blended elemental W-7 wt. %Ni-3 wt. %Fe powders were mechanically allo yed in a planetary ball mill and a heavy duty attritor. The structural and morphological characteristics of the as-milled powders were chara cterized by x-ray diffraction and electron microscopy techniques. A te rnary solid solution of Fe and Ni in W formed in both the cases; the a mount of Ni and Fe dissolved is higher in the attritor-milled powder t han in the ball-milled powder. Morphologically, the W-rich particles i n the attritor-milled powders were spheroidal, smaller in size, and sh owed a narrower size distribution than in the ball-milled condition. T hese differences led to increased density in the attritor-milled powde r compact and significant differences in chemical composition of the m atrix region and W-rich grains. Transmission electron microscopy inves tigations of the matrix region in the compacts revealed the presence o f Fe2W precipitates uniformly distributed in an Ni(Fe, W) matrix.