An assessment of grain size effects on transformation temperatures and hysteresis in Cu-based SMA tapes obtained by melt spinning

P. LA ROCA, L. ISOLA, C. SOBRERO, M. F. GIORDANA, A. ROATTA, PH. VERMAUT, J. MALARRIA

Chicago

Conferencia; International Conference on Martensitic Transformations (ICOMAT); 2017

We systematically studied the grain size, d, dependence of the shift intransformation temperatures and the widening of the hysteresis in polycrystallineCu-based shape memory alloy tapes obtained by melt-spinning. Within aphenomenological thermodynamic framework, we analyze changes in the differencein Gibbs free energy between the martensite and the parent phase, which resultfrom contributions of martensite-martensite interface energy, stored elasticenergy, and dissipative effects produced by internal friction between mobileinterfaces and grain boundaries. Experimental results (Ms vs d, and Hys vs d) are adequately fitted by functions of the characteristic grainsize of the specimens, over the range of ~100 µm to ~ 1 µm