The amount of primary metals mined (mainly steels, aluminium, etc.) has been rising steadily over the last few decades. Particularly for steels, the global recycling accounts for ~25% of the total steel produced. In EU and US, these rates are even higher (~60% and ~70%). That is attributed to low consumption, better recycling infrastructure and manufacturing practices [1,2]. To achieve the vision of a fully circular economy, the amount of secondary metals must reach ~100%. From a reusability point of view, steel is usually downcycled or thrown away as end-of-life scrap thus reducing its value. One of the main obstacles in achieving a similar use or even better products (value increase) is the accumulation of impurities, also known as tramp elements [3–5]. In the current project, we are aiming to develop a methodology for rapid innovation in scrap-based alloy design and to apply it to develop demonstrator alloys that are tolerant to the accumulation of impurities. We aim to use this methodology to focus on developing low alloyed steel grades for applications in automotive industry.

One model study that we present here is Fe and Fe-Cu systems both from a thermodynamic and characterization perspective. Cu addition in steels makes it susceptible to loss in hot ductility and hot shortness. These issues are attributed to segregations at grain boundaries and surface of the produced sample respectively. In our present study, we produced samples in form of small coins (5-10 g) in an arc melter under protection Ar gas, which was then remelted using laser confocal microscopy [6]. The material was remelted at around 1500˚C and in-situ characterized during solidification with respect to Cu segregation at different cooling rates and different amounts of Cu. The samples are further characterized by SEM-EDS, APT and other associated techniques to confirm Cu-segregations and their location. The knowledge of this process provides us input to test the given solidification models (e.g.: Scheil solidification [7]) and account for the possible segregation of Cu during different manufacturing processes. In the future, this knowledge can be applied as an input parameter for alloy design to reduce Cu segregation by controlling the amount of Cu, austenite content, cooling rate, etc.