New electromagnetic manufacturing processes for semisolid alloys and metal matrix composites synthesis

Ch. N. Vives

Laboratoire de Magnetohydrodynamique, Universite d Avignon, France

Abstract
The working principle and the peculiarities of new electromagnetic rheocasters, which are based on the use of rotating permanent magnets and which allow the production of intense three-dimensional multiphase flows in solidifying semi-solid alloy slurries and metal matrix composites, are described. These processes can be applied to the direct continuous casting of billets, tubes and slabs and are characterized by very low electric power consumption. Local measurement techniques are applied to the study of the evolution of non-newtonian magnetohydrodynamic multiphase flow phenomena with the rotational speed of the inductor, the solid fraction of the aluminum alloy matrix and the size and the volume percent of SiC particles. A discussion is presented relating the metallurgical findings to the heat and three-phase flow measurements. Some results concerning the thixoforming of these materials are also presented. Figs 7, refs 6.