Internship - R&D Metallurgist engineer

Constellium is a world leader in the development and manufacture of high value-added aluminum products and solutions for a wide range of markets and applications, focusing in particular on aerospace, automotive and packaging. Constellium also has nearly 12,000 employees worldwide.

We are committed to minimizing the environmental impact of our operations and improving the environmental footprint of aluminum throughout the value chain.

In our company, safety is essential, it is one of our core values. Our Research and Technology Center, C-TEC Constellium Technology Center, employs about 240 people. Our research is mainly in the field of casting, aluminum transformation and surface treatment.

By joining our company, you will discover a multicultural company which is committed to diversity and the well-being of its employees.

Intership's topic: Impact of process conditions on the behavior of intermetallic phases in a recycling-friendly aluminium alloy

Key words: Mechanical and microstructural characterization, ex-situ and in-situ indentation measurements, hot rolling simulation, Aluminium alloy, End-of-life recycling

Context:

Due to its low density, aluminium (Al) is a key material for sustainability as it allows lightweighting. In the transportation industry, this means fuel consumption reduction and thus lower CO₂ emissions, or increased autonomy for electrical vehicles. However, producing primary Al from bauxite ore is very energy intensive, especially the electrolysis step in which alumina oxide is refined and transformed into metal aluminium.  So, it is interesting to massively use recycled aluminium, meaning remelting Al scrap to make new ingots. Indeed, only 5% of the energy required to produce primary Al is needed to remelt used Al. In principle, Al can be recycled endlessly. However, only one third of Al produced today is made from scrap, resulting in significant greenhouse gas emissions. Increasing this ratio in the coming decades and operating a significant shift from primary synthesis (ore reduction) to secondary synthesis (scrap melting) require designing new alloys, able to tolerate more impurities. The project of the internship is linked to the development of a new alloy grade permitting to absorb a significant amount of automotive End of Life (EoL) scrap. This comes hand in hand with a change in the microstructure of the material and a strong increase of the number of secondary phases due to contaminants brought by the recycling loop. These microstructural changes may lead, without adapted process adjustment to decreased ductility.

Objectives:

The objective of this project is to investigate how to modify these secondary phases through the downstream transformation (homogenization, hot-rolling conditions). In fact, during homogenization, phases may transform and then, be more or less fractured during hot-rolling depending on their chemistry and brittleness. In order to evaluate this behavior, hot rolling simulations will be performed at C-TEC with a thermo-mechanical equipment (Servotest). Particles fracture will be quantified and in parallel, the same samples will be subjected to in-situ hot tensile tests and micro-indentation to characterize the behavior of particles during Constellium processing.  Moreover, room temperature nano-indentation (possibly within the SEM) will be performed to investigate the behavior of these same phases during stamping at the customers. These indentation experiments will be conducted at the SiMAP laboratory, together with lab tomography to link damage to the 3D morphology of the phases. The goal is to link the material changes (phase transformation of the particles) to mechanical properties such as their fracture toughness as a function of the process parameter (temperature, deformation). For this, the candidate will spend about 50% of his internship with the academic partner.

The project has several components:

• Literature review to identify the possible intermetallic phases in the targeted alloy and the methods used to probe mechanical behavior of such phases
• Hot rolling simulation with a Servotest machine (high temperature, high deformation)
• Microstructural characterization of the phases before and after hot rolling simulation (optical microscopy, scanning electron microscopy with EDX for chemistry measurements, lab tomography)
• Sample preparation for indentation measurements, especially for in-situ SEM indentation
• Indentation measurements to link the results with microstructural changes induced by the process
• Analysis and synthesis of the results, report writing and presentation to the team

The intern will be part of a R&D team of engineers working on the development of recycling-friendly alloys. The internship work is strongly experimentally oriented. After the necessary training, the candidate will have to coordinate the sample preparation and characterization between C-TEC and SIMaP laboratory.

Education level: Engineering school or Master of Science

Competencies (technical & soft skills requirements):

• Good knowledge in physical metallurgy
• Motivation for experimental work
• Strong capacity to post-treatment and analyze a significant amount of data
• Serious, autonomy, critical mind and creativity
• Candidate interested in research and development
• Good English level, both written and spoken