Author(s)

M. Tercelj, P. Cvahte, I. Perus & G. Kugler

Abstract

Almost pure aluminum composite, P/M Al-special, with an average grain diameter of 1μm with oxides on the grain surface was produced by a powder metallurgy route. Billets were extruded on an indirect press at various temperatures and ram-speeds. Specimens made from an extruded profile were additionally annealed at 300ºC at various times. Hot workability of these various initial states was studied by hot compression tests in the strain rate range 0.01– 10 s-1, the temperature range 300–580ºC up to a strain of 0.9. Additionally tensile tests were carried out to determine the mechanical properties on specimens previously annealed at 300ºC. The oxide surface prevents grains coarsening during hot deformation and consequently excellent mechanical properties of the specimens annealed at a temperature of 300ºC were obtained. Keywords: P/M 1080 Al composite, hot extrusion, annealing, hot compression, mechanical properties. 1 Introduction Demands for weight reduction of parts applied in cars and aircrafts has lead to the replacement of conventional materials with lighter and stronger materials. Aluminum alloys have a great potential for this application but their weaknesses are too low strength and stiffness. On the other hand production of parts from metal-matrix composites which is based on the reduction of grain size is very promising due to their unique mechanical properties in comparison with coarsegrained materials [1–6]. Powder (P/M) and ingot metallurgy which include particle reinforcement mixing with solid or molten metal assure production of composites with

Keywords

P/M 1080 Al composite, hot extrusion, annealing, hot compression, mechanical properties