Two single crystals with compositions Fe-Ni-Co-Al-Ta and Fe-Ni-Co-Al-Ta-B were selected and fabricated by Bridgman method. Subsequently, ingots were homogenized, oriented and subjected to a two-step heat treatment process in order to obtain fine and coherent γ' precipitates. Subsequently, superelastic cycling experiments were performed at 77 K. The next step included detailed microstructural characterization using transmission electron microscopy and high-energy synchrotron X-ray diffraction measurements together with Rietveld refinement. The results show that the number of fully reversible superelastic strains is very sensitive to the size of γ' precipitates. The smaller (3 nm) γ' precipitates ensured more superelastic response compared to material with larger γ' particles size (5 nm), in which the material did not receive its original shape after 10 cycles even after being heated.

Two different principles of TMF-testing were investigated for the wrought aluminium alloy AlCuBiPb (201 I). In the first testing method the specimens are clamped in a stiff load frame. A cyclic temperature load is applied, which leads to an out-of-phase (OP) TMF loading. The local strain is measured within the parallel cross section of the specimen. The second series of OP-TMF tests are conducted using closed loop strain control on a servo-hydraulic TMF testing system, which guarantees a rigid restraint condition within the parallel section of the specimen. To compare these two principles of TMF-testing, additional experiments were conducted with different mechanical strain amplitudes. The two experiments can be compared well, when the local strains are taken into account. Therefore, the method of the rigid clamped specimen can be used to get experimental data in a wide range of strain amplitudes.