Internal friction study on fcc/hcp martensitic transformations in thermomechanically treated Fe–28Mn–6Si–5Cr–0.53Nb–0.06C (mass%) alloys

We have studied the temperature dependence of the internal friction and Young's modulus of the Fe–28Mn–6Si–5Cr–0.53Nb–0.06C (mass%) alloys with or without NbC precipitates produced by three thermomechanical treatments: (i) solution treatment, (ii) rolling at 870 K and subsequent aging at 1070 K, and (iii) rolling at 1070 K, in the vicinity of the forward (Ms) and the reverse (As) martensitic transformation temperatures using a dynamic mechanical analyzer (DMA). The specimen subjected to rolling at 870 K and subsequent aging showed the highest Ms temperature and the largest amount of the hcp martensite. The solution treated specimen showed the lowest Ms temperature and the minimum amount of the martensite. The magnetic susceptibility measurements made by means of a superconducting quantum interference device (SQUID) revealed that the martensitic transformation is hindered by the preceding magnetic transition from the paramagnetic (cubic) phase to the antiferromagnetic (tetragonal) phase.