Impact of recycling on the formability of automotive aluminium sheets
The use of aluminum alloys for automotive applications is growing rapidly, as this is one of the main ways to reduce GHG emissions from cars by reducing their weight, in the context of regulations imposing drastic reductions in the coming decades.
At the same time, an increasing proportion of the aluminum used is derived from recycling processes, which can lead to variations in alloy composition, particularly with respect to impurities. In the 6000 series of alloys (Al-Mg-Si-Cu), the increased presence of elements with low solubility and mobility, such as Mn and Fe, can have a significant impact on the plastic properties of the alloys, especially on their formability and crashworthiness. This impact depends in a complex way on the properties of the aluminum matrix hardened by the more mobile alloying elements (Mg, Si, Cu) and on the transformation parameters (solidification, homogenization, hot and cold deformation), which influence the spatial distribution, shape, size, and crystallographic nature of the intermetallic phases formed.
The objective of the thesis is to achieve a better understanding of the effect of microstructural parameters of Fe and Mn based intermetallics and dispersoids, coupled with the properties of the Al matrix, on the plasticity and formability properties of the alloys. For this purpose, the approach will be the generation of a large number of microstructures, coupled with systematic characterization of microstructures at different scales and mechanical properties of interest.
Given the complexity of the link between the microstructural parameters and the expected mechanical behavior, a machine learning methodology will be adopted to establish this link and thus decorrelate the effect of the different parameters by evaluating by the model the shaping properties associated with microstructural states and mechanical properties not achievable experimentally.
PhD student:
Pierre Guérin
Supervision:
Alexis Deschamps, Frédéric De Geuser, Pierre Lhuissier – SIMaP
Massih-Reza Amini – LIG
Fanny Mas, Constellium