Papers by Author: Dan Frunză

Abstract: Thixo-extrusion processing could become an important technique to extend the range and complexity of extruded profiles. This work presents the results of thixo-extrusion process applied on aluminium alloy and they were carried out with both computer numerical simulation and experimental methods. The thixo-extrusion set-up was made. Backward extrusion tests were particularly studied and simulated using Forge 2005 software. The constitutive equation used for these simulations is based on a micro-macro model for the semi-solid evolution. The constitutive equation parameters were identified due to comparisons of the simulated load-displacement responses with experimental ones for backward extrusion tests on 7075 semi-solid aluminium alloy, for different temperatures.

Abstract: The paper presents the experimental results on an aluminum alloy and a silver alloy processed by equal channel angular extrusion in order to refine the grains. Two type of extrusion dies have been used for experimental works: one with fixed walls and the other one with movable walls in order to reduce the friction during extrusion process. The new concept of the die consists in simultaneously pressing of two samples in one entering channel with two opposite exit channels. The channel geometry, friction contact, strain rate, extrusion load and micro structure aspects are presented.

Abstract: The present paper presents experimental results on Al foam produced by powder metallurgy method. Their lightweight property makes them attractive for the cores of structural sandwich panel in products ranging from sport equipment to lightweight building panels. The process of metallic foam manufacture as well as the testing methods used for the characterization of their physical, mechanical and chemical properties will be exposed.

Abstract: Some of new severe plastic deformation processes as equal channel angular extrusion, and strip shearing are presented as very efficient techniques for grain refinement. Channel geometry, contact friction, strain rate and multi-pass processing versus microstructure and mechanical properties are shown.