Department Microstructure and Residual Stress Analysis

Engineering materials

New aluminium alloys increase their recycling content using scrap from other recycled aluminium alloys. This reduces the carbon footprint and creates a close loop of recyclability. But increasing recycling content brings several metallurgical and scientific challenges. Using more scrap and reducing amount of primary aluminium usage means to augment the quantity of alloying elements like Fe, Si, Mg and Zn in aluminium alloys. Tolerance of aluminium to these alloying element is particularly important in the design of an aluminium alloy. This is due to the low solubility that aluminium has for many elements (especially for iron). Iron will increase the presence of intermetallic phases which are brittle and can be detrimental for mechanical properties. Understanding the crystallography, morphology evolution and network distribution of these phases in rolled aluminium sheets depending on the processing parameters is key to tailor the microstructure to improve mechanical properties of the alloys even with larger recycling content. With 3D tomography at different scales we study the the structure of the particle networks and voids and the shape and distribution of alpha and beta phases to understand how we can improve their properties. This work is supported by the company Novelis.