The march of aluminium alloys
In accordance with European regulations, the ever-increasing demands on light and cost-effective applications with ecological specifications have been the driving force for industrial evolution. To this end, RHEO-LIGHT partners exploited at the industrial level the New Rheocasting process (NRC) previously developed for light alloys and components. NRC is an aluminium semi-solid casting method carried out under high pressure to eliminate shrinkage defects of molten metals. This process was first implemented in the large scale die casting and injection moulding machines of Ube Machinery Ltd. Its prominent features in terms of precision, cycle rates and energy savings have drawn the attention of different industrial sectors. RHEO-LIGHT aim was to develop NRC-processed light alloys and components, including advanced aluminium and magnesium alloys, for automotive industries. The quality of the new alloys was assessed by experimental characterisation of aged samples for dendritic forms indicating microstructural degradation. The overall life cycle of the new constructions was validated and their cost-efficiency was evaluated. Their position in the competing field of similar processes was also estimated and feasibility studies for expanding to other industries were performed. In this work frame, a number of innovative aluminium alloys were produced applying various combinations in copper (Cu) and silicon (Si) composition to the basic AlSi7MgO. The presence of additives such as zinc (Zn), manganese (Mn) and Cu was also studied employing AlCu5MgTi as mother alloy. The new fabrications were further examined to assess their mechanical properties and their performance in the ASTM (American Society for Testing and Materials) test. Alloys with low Cu additions to the basic AlSi7MgO have already passed ASTM test giving satisfactory results. The suggested aluminium casting alloys have broad applicability to a variety of casting processes exhibiting improved performance compared to conventional ones. Therefore their leading position in the market of automotive and other structural components has already been secured.
