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Logo: Research Group 1766
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Logo: Research Group 1766
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HTSMA

Background

Shape memory alloys (SMAs) feature unique mechanical properties and thus, are attractive for a variety of applications. Currently, these range from stents or microinvasive tools used in the biomedical sector to actuators and sensors used in the automotive or aerospace industries. SMAs can recover large strains and both the shape memory effect and pseudoelasticity result from a reversible transformation between an austenitic and martensitic phase. These transformations can be thermally triggered or occur as a result of superimposed mechanical stress.

Currently, the usage of the functional properties of conventional SMAs is limited to temperature up to about 80 °C. This is a serious limitation for many of the envisaged applications. Consequently, the advent of SMAs that can operate above 100 °C has received substantial interest both from industry and academia. However, the high-temperature shape memory alloys (HTSMAs) available today rely on substantial amounts of precious elements such as Pt or Pd. Clearly, there is a need to develop low cost HTSMAs that can be easily processed. Moreover, these new alloys not only have to demonstrate large transformation strains, but also need stable microstructures that provide for reliable functional properties. The latter is of paramount importance for cyclically loaded components.

shape memory effects