Neutron diffraction phase analysis during thermal cycling of a Ni-rich NiTi shape memory alloy using the Rietveld method

Martensitic transformations in an aged Ni-rich NiTi shape memory alloy are analysed using neutron diffraction and electron microscopy. The material shows a two step transformation on cooling from B2. After the first release of latent heat on cooling two martensitic phases (R-phase and B19') are present. This is due to a heterogeneous microstructure after solution annealing and ageing. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.