Novel prestressing applications in civil engineering structures enabled by Fe-Mn-Al-Ni shape memory alloys

摘要

The present study reports on the feasibility of using Fe-Mn-Al-Ni shape memory alloys as prestressing elements in civil engineering. Polycrystalline Fe-Mn-Al-Ni specimens were prestrained and subsequently heated up under constant strain in order to evaluate the prestressing potential of the material. Due to the formation of precipitates as a function of both, maximum heating temperature and dwell time, the prestress level of the material can be tailored. Moreover, in oligocrystalline specimens prestress losses, e.g., due to shrinkage and creep of concrete, can be impeded by changing the functional properties from shape memory effect to superelasticity. Based on the results presented it can be concluded that the Fe-Mn-Al-Ni system is a promising alternative to conventional shape memory alloys used for prestressing applications eventually enabling novel and innovative applications in numerous civil engineering structures by utilizing the well-defined evolution of precipitates during activation.