This is a collaborative project in partnership with the European Space Agency (ESA) aimed at developing low thermal expansion alloys suitable for processing by Additive Manufacturing.
Among the metal Additive Manufacturing technologies, SLM (Selective Laser Melting) is the most mature, and allows complex shapes to be produced net-shape, enabling innovative designs and topological optimization of components emphasizing design for functionality rather than manufacture. First applications in astrospace for classical lightweight materials such as titanium and aluminium show great benefit compared to traditional solutions based on machining and assembly in terms of cost, schedule, weight saving, and waste reduction.
Today, only two aluminium alloys are used for AM parts, AlSi7Mg0.6 and AlSi10Mg, however their physical properties are not appropriate for certain applications and a low CTE aluminium alloy is required. Aluminium alloys with additional silicon content have been identified as good candidates for both LBM processing (flowability, melting behaviour) and space requirement matching (medium CTE, high thermal conductivity, low density). Preliminary trials have been conducted recently by the University of Birmingham on several combinations of mixed powders (Al with various ratios of Si) with very encouraging first results. Fine microstructures can be achieved under certain processing conditions as well as good tensile properties and CTE values.
Through the proposed study, the University of Birmingham will develop a new powder suitable for LBM, AlSix, and the associated machine parameters necessary to manufacture components. This information will then be transferred to the industrial partners for further development.