Precipitation Hardening Behaviour of Al-2Sc Micro Sheets

Abstract

The continuous miniaturisation of products needed e.g. in the automotive or the micro electronic sector requires process chains which allow the manufacturing of microscopically small components in high quantities. The development of the required processes and technologies is the aim of the Collaborative Research Centre 747 “Micro Cold Forming” of the German Research Foundation. A necessary step in the manufacturing process chain is the heat treatment, which enables the adjustment of the semi-finished micro components to cold forming. Finally the usage properties have to be adjusted e.g. by precipitation hardening of aluminium alloys in order to increase the strength above the strain hardened level. To achieve a high strength aluminium alloy with elevated temperature stability in form of thin foils a new Al-Sc alloy with 2 mass-% scandium had to be developed within the Collaborative Research Centre. In comparison to conventional casting techniques it was possible to suppress Al3Sc precipitation and to ensure the supersaturated solid solution by using a Physical Vapour Deposition (PVD) Magnetron Sputtering process and low sputtering temperatures. Samples of the material are then artificially aged and characterised by ultra micro hardness measurements to evaluate the optimal ageing parameters. Besides this the microstructure was determined by light microscopy and Transmission Electron Microscopical (TEM) analysis.