Investigation and improvement of the corrosion behavior of Fe-Mn-Al-Ni(-Cr) shape memory alloys

铁基形状记忆合金（SMAs）的腐蚀行为的基本知识是至关重要的，为了使这些SMAs符合新材料密集型应用的要求，如桥梁和摩天大楼的阻尼元件。特别是Fe-Mn-Al-Ni作为最有前途的铁基合金体系之一，在初步试验中表现出较高的腐蚀敏感性。为了弥补目前的研究空白，本项目将研究Fe-Mn-Al-Ni的基本腐蚀机制。此外，用铬代替铁和铝可以改善合金的腐蚀性能。因此，应对合金体系进行钝化处理，以保证在马氏体相变破坏表层的情况下再钝化。此外，还将进行碱性和酸性溶液中的腐蚀实验，以验证SMA在土木工程中的各种应用。

A fundamental knowledge of the corrosion behavior of iron-based shape memory alloys (SMAs) is crucial in order to qualify these SMAs for new material intensive applications such as damping elements for bridges and skyscrapers. Especially Fe-Mn-Al-Ni, as one of the most promising iron-based alloy systems, shows a high susceptibility to corrosive attack in preliminary tests. In order to tackle current research gaps, the fundamental corrosion mechanisms of Fe-Mn-Al-Ni will be investigated in this project. Moreover, the corrosion behavior will be improved by the substitution of chromium for iron and aluminum. Thereby a passivation of the alloy system should be obtained, which has to guarantee repassivation in case the surface layer gets damaged by the martensitic transformation. Furthermore, corrosion experiments in alkaline and acid solutions will be carried out to qualify the SMA for diverse applications in civil engineering.