A Microscale Model for Ausferritic Transformation of Austempered Ductile Irons

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• 作者：Adrián D. Boccardo ; Patricia M. Dardati…
• 刊名：Metallurgical and Materials Transactions A
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：48
• 期：1
• 页码：524-535
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Characterization and Evaluation of Materials; Structural Materials; Surfaces and Interfaces, Thin Films; Nanotechnology;
• 出版者：Springer US
• ISSN：1543-1940
• 卷排序：48

文摘

This paper presents a new metallurgical model for the ausferritic transformation of ductile cast iron. The model allows predicting the evolution of phases in terms of the chemical composition, austenitization and austempering temperatures, graphite nodule count, and distribution of graphite nodule size. The ferrite evolution is predicted according to the displacive growth mechanism. A representative volume element is employed at the microscale to consider the phase distributions, the inhomogeneous austenite carbon content, and the nucleation of ferrite subunits at the graphite nodule surface and at the tips of existing ferrite subunits. The performance of the model is evaluated by comparison with experimental results. The results indicate that the increment of the ausferritic transformation rate, which is caused by increments of austempering temperature and graphite nodule count, is adequately represented by this model.