Iron-based shape memory alloys for civil engineering structures: An overview

• The development of iron-based SMAs is presented, focusing on features for civil engineering.
• Differences between the martensitic transformation in Ni–Ti and Fe–Mn–Si SMAs are highlighted.
• High recovery stresses, which are necessary for prestressing, can be obtained for FeMnSi alloys.
• Pilot experiences on the application of FeMnSi alloys are presented.
• This paper collects unsolved aspects for future research.

Iron-based shape memory alloys (SMAs), especially Fe–Mn–Si alloys, are materials that have great potential in civil engineering structures, but their application is still in a pioneer stage. Recent developments in alloy composition and manufacturing envisage new perspectives, especially in the field of repairing structures as well for new structures, when using these SMAs as prestressing tendons. This paper presents the fundamentals of the martensitic transformation from an engineering perspective as well as some key properties, such as recovery stress, corrosion resistance, weldability and workability. Finally, some unsolved aspects are collected, and new perspectives for the use of these SMAs are presented.