Some properties of multi-layer pm aluminium matrix composites after hot closed - die forging
Stefan Szczepanik, Marek Wojtaszek
Quarterly No. 3, 2009 pages 256-259
DOI:
keywords: aluminium matrix composites, layer materials, closed - die forming, mechanical properties
abstract Manufacturing of layer specimens with gradient chemical compositions from mixtures of aluminium RAl1 and aluminium alloy Al17Si5Fe3Cu1.1Mg0.6Zr (designated Al17) was investigated. The preforms were manufactured by cold pressing - such that the concentration changed from 0 to 60% alloy at 20% intervals. Preforms and gradient layer preforms were closed - die forged at 485oC on a screw press. The structure and the mechanical properties after forging and additional heat treatment were investigated. Microstructure examination indicated no porosity in all samples. The influence of chemical composition on mechanical properties in tensile, bending and compression tests was examined. With increasing Al17 content, an increase in the compression and bend strengths appeared. Highest tensile strength was recorded for 40% Al17 content. The critical strain during a compression test decreased with an increase of Al17 powder in the composites. The multi layer materials were manufactured as the composites. The dependences of the bend strength on construction of specimens, gradient of chemical composition and manner of their loading were analysed. Tests were carried out parallel to the concentration gradient in these specimens. Layer Al-60%Al17 on top of the specimens (specimen DCB) resulted in higher values than when the top layer had the highest aluminium concentration (specimen BCD).