Development and evaluation of preparation process of composite materials in powder systems with different physical properties using fine mixing and kneading

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We have proposed the method for estimating experimentally the net energy applied to the particles in equipment for compounding the particles. In the method, the spherical copper particles, of which the stress-strain relation is known, are used as the standard material. The method has been applied to a high-speed elliptical-rotor-type powder mixer (HEM) to which Zirconia beads were added to aid stress transmission. The net applied energy has been estimated by measuring the deformation of copper particles after processing under various operating conditions. To investigate the energy transmission from the elliptical rotor to the particles via the beads, the motion of beads has been analyzed by using the discrete element method. By utilizing the results of experiment and calculation, the composite particles with a desired feature (shape, surface condition, size distribution, etc.), which consists of fine alumina particles (guest particles) and copper particles (host particles), can be prep … More ared. The green body of which the internal structure is homogeneous or regular heterogeneous can be manufactured by the compression forming of the composite particles thus obtained.Flowability of metal particles used in metal-injection-molding (MIM) process has been evaluated by performing the shear test using the rotary-intrusion-type powder rheometer with a conical rotor. The dynamic friction coefficient measured is closely related to the characteristics of melt injection of metal particles, and considerably changes after the surface modification of metal particles by the HEM.The plasticity of metal particles can be modified by controlling the surface condition of metal particles.In the development and evaluation of powder materials including fibers, the powder-fiber interaction and the characteristics of structure of the powder-fiber mixture have been clarified by newly developed testers. The optimum features of granules of the mixture and the optimum operating conditions in the granulation have been determined. Less