Experimental works are done to assess the seismic behavior of concrete beams reinforced with superelastic alloy (SEA)
bars. Applicability of newly developed Cu-Al-Mn SEA bars, characterized by large recovery strain, low material cost,
and high machinability, have been proposed as partial replacements for conventional steel bars in order to reduce
residual deformations in structures during and after intense earthquakes. Four-point reverse-cyclic bending tests were
done on 1/3 scale concrete beams comprising three different types of specimens - conventional steel reinforced concrete
(ST-RC), SEA reinforced concrete (SEA-RC), and SEA reinforced concrete with pre-tensioning (SEA-PC). The results
showed that SEA reinforced concrete beams demonstrated significant enhancement in crack recovery capacity in
comparison to steel reinforced beam. Average recovery of cracks for each of the specimens was 21% for ST-RC, 84%
for SEA-RC, and 86% for SEA-PC. In addition, SEA-RC and SEA-PC beams demonstrated strong capability of recentering
with comparable normalized strength and ductility relative to conventional ST-RC beam specimen. ST-RC
beam, on the other hand, showed large residual cracks due to progressive reduction in its re-centering capability with
each cycle. Both the SEA-RC and SEA-PC specimens demonstrated superiority of Cu-Al-Mn SEA bars to conventional
steel reinforcing bars as reinforcement elements.
Ferromagnetic Shape Memory Alloy (FSMA) particulate composites are processed using Spark Plasma Sintering (SPS) with various weight fractions of NiTi (51 at% Ni) and Fe powders. The magnetic properties of these composite specimens were experimentally evaluated using Vibration Sample Magnetometry (VSM). A model for calculating the effective magnetic properties has been presented in this work where Eshelby's inhomogeneous inclusion method considering Mori-Tanaka's mean field theory for larger concentrations of Fe has been used to predict the effective magnetic properties. The analytical results thus obtained are compared with experimental data resulting in a reasonably good agreement.
Effect of the magnetic field on the martensitic transformation of Co-Ni-Al single-crystal was investigated by differential thermal analysis (DTA) and the in-situ microstructure observation under magnetic field. The martensitic transformation temperatures Ms and Mf of the Co34.5Ni35.5Al30 single-crystal specimen showing the martensitic transformation from the paramagnetic austenite (B2) to the ferromagnetic martensite slightly increased under the magnetic field and those temperature shifts were about 1.3°C at 1.0T. It was also observed in the Co34.5Ni35.5Al30 single-crystal specimen that the phase boundaries between the austenite and the martensite slightly move by applying the magnetic field of 1.0T. These results are discussed on the basis of a thermodynamic stabilty of the martensite phase under the magnetic field. The martensitic and the magnetic transformation behaviors of the Ni-Al-Co alloys are also reviewed.