THE INFLUENCES OF POWDER MIXING PROCESS ON THE QUALITY OF W-CU COMPOSITES

Abstract

The mixing homogeneity of powders has a significant influence on the quality of composites fabricated from a powder metallurgy process. The factors that influence the homogeneity include the powder mixer, the medium, and the ball-milling procedure. In this paper, the influences of powder mixers and mixing media on the quality of tungsten-particle reinforced copper matrix composites are studied. Apart from dry mixing, other media used in the wet mixing process include n-butyl alcohol, camphor oil, and paraffin oil. Comparisons on mixing feature are made to a TURBULA® mixer and a Random mixer. The TURBULA® mixer is commercially available, and the Random mixer is an in-house designed machine. Our results show that using paraffin oil as the mixing medium, one may obtain optimal homogeneity in the composites. The Random mixer is superior to the TUBULA® mixer due to the fact that the Random mixer offers an avalanching motion creating pure shear forces onto the powders.