Final Report Summary - SMARTMET (Adaptive nanostructures in next generation metallic materials: Converting mechanically unstable structures into smart engineering alloys) The main goal of SMARTMET was to address the inverse strength-ductility problem of metallic alloys. This relation has for centuries set an apparent limit to the mechanical optimization of advanced engineering alloys. The basis to pursue this new design strategy was the use of experiments (PI) and atomic-scale theoretical tools (Co-PI) with the specific approach of understanding, tuning and exploiting phase instability, enabling in particular athermal deformation mechanisms.The goals of SMARTMET have been reached leading to significant achievements, for instance in the field of novel strong and ductile TRIP and TWIP high entropy alloys, metastable Ti alloys and weight reduced nanoprecipitation hardened FeMnAlC steels. Extensive simulation efforts in concert with advanced multi-scale characterization down to atomic scales have for instance shown that the so-called Gum Metal Ti alloy family shows multiple, previously unknown, phase transformation phenomena: e.g. a reversible nanotwinning-assisted backpack transformation. A detailed ab initio analysis lead to a fundamental understanding on the electronic scale of the phase stabilities in Ti and the experimentally investigated alloys. We expect that the results of our study will have important technological consequences, because they allow predicting composition ranges for designing special multiphase Ti alloys. Other successfully followed SMARTMET routes involved the combined experimental-theoretical investigation of high entropy based multicomponent alloys at the verge of their stability as well as ductilized Mg solid solution alloys. Previously believed concepts regarding the dominance of configurational entropy were shown to be inappropriate both by experiment and theory within SMARTMET.
