Hot forming by consolidation and extrusion of Al-Si-Fe-Cu powder and mixture of this powder and 10% SiC particles
Marek Wojtaszek, Stefan Szczepanik, Karolina Doniec Akademia Górniczo-Hutnicza, Wydział Inżynierii Metali i Informatyki Przemysłowej, al. Mickiewicza 30, 30-059 Kraków
Quarterly No. 2, 2006 pages 44-49
DOI:
keywords: Al-Si-X alloys, composites, SiC particles, powder metallurgy, hot consolidation in closed-die, hot extrusion
abstract The work presents the results of research of the materials obtained from powder using the technology that combined metal forming and powder metallurgy. Semi-finished products designed for the extrusion were produced by hot consolidation in closed-die the Al17Si5Fe3Cu1.1Mg0.6Zr powder and mixture of this powder and 10 vol.% of silicon carbide particles. Consolidation process was performed at 530°C, at unit pressure 300 MPa and with stamp pressing time of 7 minutes. The semi-finished products obtained in this way were extruded at 530°C, at a traverse speed of 0.1 mm/s and at extrusion ratio λ = 13.7. The values of the forces which appear during extrusion in 530°C as a function of punch displacement were registered. The relative density (Fig. 3) and hardness (Fig. 4) for materials after hot consolidation and extrusion. The compression strength at room temperature (Fig. 5) and the abrasive wear (Fig. 6) for the extruded products were investigated. The fracture surfaces in a bending test at room temperature (Fig. 8) and the structures (Fig. 7) of hot extruded materials were estimated. Extrusion at 530°C caused material processing with invariable of relative density value. The addition of silicon carbide particles causes only insignificant drop in density of composite materials, in a range of 0.2÷0.3%. Introducing the reinforced phase in the matrix leads to the increase of product hardness The hardness of materials obtained by hot extrusion was lower than for semi-products by the some chemical composition, after hot consolidation in closed-die. In the case of the materials manufactured by hot extrusion, addition 10% of silicon carbide particles leads to the increase of the compression strength and abrasive wear results. The destruction surface of the materials, obtained by hot extrusion arose as a result of brittle cracking. Observation of the hot extruded products microstructures was confirmed by qualitative density measurements results (Fig. 7).