PHYSICAL MODELING OF THE PLASTIC FLOW IN THE EXTRUSION PROCESS OF LAYERED COMPOSITE MATERIAL USING DIFFERENT DIE GEOMETRY

摘要

The results of physical modeling of the extrusion of layered composite, in particular dealing with the influence of the die geometry on the character of plastic flow of the core-sleeve system composite have been presented. The influence of the concentric arrangement of components in the initial billet as hard core and soft sleeve on final effect of simultaneous plastic flow of various materials to obtain required layered composite has been analysed. The model materials like soft lead, hard lead alloy soft and hard plasticines and set of the dies of different geometry has been used in experimental procedure of direct extrusion. The experimental results of the extrusion of composite material using flat, conical and convex dies indicate possibility to obtain advantageous flow pattern for suitable convex dies. Basing on the analysis of the character of plastic flow (basing on visioplasticity method) with taking into account relative velocity distribution in the orifice region, size and shape of the deformation zones and extrusion load in particular the best convex die geometry in comparison with others has been proposed. Basing on analysis of different results of the co-extrusion of different materials e.g. relatively small plastic zone, relatively low extrusion load and equalization of velocities of particles in the region the die orifice may indicate adequate convex die geometry for realizing extrusion process of composite material of the core-sleeve structure.