Mechanism of the As temperature increase by pre-deformation in thermoelastic alloys

The Ti-Ni-Nb shape memory alloys are attracting recent attention for the wide transformation temperature hysteresis, whih is caused by the A s increase due to pre-deformation, since it is suitable for pipe couplings. To find out the origin for the A s increase by pre-deformation, similar investigation was made by tensile tests, electrical resistance measurements, optical microscopy and transmission electron microscopy (TEM), for a Cu-13.8%Al-4.0%Ni (mass%) single cyrstal and Ti-50%Ni and Ti-50.5%Ni(at%) polycrystals, which exhibit the thermoelastic martensitic transformation

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