Abstract
The heterogeneity of powder bulk density formed in the compacted powder has a great influence on the mechanical strength and the dimension accuracy of the final product. However, the formation mechanism of powder bulk density distribution in the powder compact has not yet been sufficiently clear up to now. To elucidate the formation mechanism, the refraction phenomenon of loose bulk density zone through the interface between powders was investigated and discussed. And it was pointed out that the refraction condition between powders can be described by "the difference between the incidence angle aA and the refraction angle aB of a loose bulk density zone to and from the powder interface coincides with that between the internal friction angles φA (incidence) and φB (refraction) of powders." This condition was experimentally checked by X-ray radiograph of the refraction phenomena of loose bulk density zone produced in powder.
