Physical modeling of plastic flow in the KOBO extrusion process using dies of different geometry

摘要

The paper presents results of extrusion effects which are the basis of physical flow modeling under conditions of the KOBO process, which allow to determine the influence of the type of dies with different geometrical parameters on the scheme of the plastic flow of the metal. Billets made of alternating slices of 7075 T6 aluminum and copper (M1E) were used as composed initial material for extrusion. The process was performed using dies of different face geometry, without heating the billets and press parts. Copper layers have been used as markers for the identification of flow patterns and plastic zone while at the same time demonstrating the possibility to obtain a metallic composite material Al-Cu. Specimens from extruded products as well as butts were tested for macro and microstructure analysis and mechanical properties. All specimens, regardless of which products part they were collected, were characterized by favorable, homogeneous fine-grained microstructure throughout the volume of the product. Connection zone between Al and Cu is inseparable, devoid of defects. Obtained composite material has very good strength, similar to that of the 7075 T6aluminum alloy. The obtained results of the experimental work indicate goal of modification of the features of tools for the KOBO extrusion process as having a direct influence on the process parameters and the plastic deformation of the billet. The mechanical and structural characteristics of the KOBO extruded products, the flow scheme under various conditions of the process parameters and the extrusion force depended on the type of dies have been presented.