Nanoprecipitation effects on phase stability of Fe-Mn-Al-Ni alloys

P. LA ROCA, A. BARUJ, C. SOBRERO, J. MALARRIA, M. SADE

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2017 vol. 708 p. 422 - 427

0925-8388

Early stages of coherent precipitation have beenstudied in several Fe-Mn-Al-Ni samples aged at 200 C for different timeintervals in order to analyze the effect of nanoprecipitation on the phasestability during thermally induced martensitic transformations. The α-γ?martensitic transformation was studied by means of dilatometry measurements.Transmission electron microscopy (TEM) observations were performed in order tocharacterize the microstructure of the samples. The size and volume fraction ofnanoprecipitates were evaluated for the as-quenched material and samples agedfor 10, 20 and 180 min. Considering these data and additional high resolutionTEM results reported in the literature a phenomenological model is presentedthat enables understanding the effects of B2 precipitates on the relative phasestability between austenite and martensite, and their influence on the observedpseudoelasticity of this metallic system. With this model, the changes of themeasured transformation temperatures can be predicted with considerableaccuracy.