Amplitude Dependence of Dynamic Young's Modulus of CuZnAl Alloys near Martensitic Transformation

Department of Physics, University of Perugia, Perugia, Italy

Abstract

The dynamic Young's modulus E of CuZnAl alloys displays non-linear behaviour in the vicinity of the martensitic transition as it decreases with increasing the amplitude of vibration.The difference AE between the Young's modulus measured at the lowest strain e₀ and that at the current strain e shows a double peak in the transition region, both during heating and cooling.These peaks are believed to be associated with some lattice instabilities such as those leading from the austenitic β₁ and β₂ phases to the β’₁ and β’₂ martensites, respectively.The observed elastic non-linearity appears to be a bulk lattice effect.as it occurs even over temperature regions far above M_s’ where the system is a homogeneous single phase.