Influence of alloy element distributions on austempered ductile irons

PATRICIA M. DARDATI; LUIS A. GODOY; ADRIÁN D. BOCCARDO

MATERIALS SCIENCE AND TECHNOLOGY

MANEY PUBLISHING

Lugar: London; Año: 2018

0267-0836

The influence of alloy element distributions on austempered ductile iron microstructure and austempering treatment was analysed by a cellular automaton model that considers the ausferritic and martensitic transformations. The initial microstructure is modelled as spherical graphite nodules inserted in an austenitic matrix, in which the alloy elements are distributed in a uniform or non-uniform way. The study is performed for different chemical compositions and graphite nodule sizes. Delays in the development of ausferritic transformation are produced by the increment of graphite nodule size and the presence of alloy element microsegregations. Moreover, microsegregation reduces the final volume fraction of ferrite platelets. The predicted retained austenite volume fraction is in good agreement with experimental measurements reported in the literature.