NONLINEAR ELASTIC PROPERTIES OF CUZNAL ALLOYS NEAR MARTENSITIC-TRANSFORMATION

The amplitude dependence of the dynamic Young modulus has been investigated during temperature cycling in the vicinity of the martensitic transformation. The Young modulus E is smaller at higher vibration amplitudes. On cooling, the difference Delta E between the value of E at the lowest strain epsilon(0) and at the current strain E passes through a pronounced structured maximum in the transition region. On heating, Delta E shows a hardly noticeable peak, followed by a steep decrease over the reverse transition region. Non-linear effects also occur far above the martensite start temperature M(s) and are the result of precursor effects.