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arXiv · 2101.07468

Role of interface morphology on the martensitic transformation in pure Fe

Pawan Kumar Tripathi·Shivraj Karewar·Yu-Chieh Lo·Somnath Bhowmick
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Abstract

Using classical molecular dynamics simulations, we study austenite to ferrite phase transformation in iron, focusing on the role of interface morphology. We compare two different morphologies; a \textit{flat} interface in which the two phases are joined according to Nishiyama-Wasserman orientation relationship vs. a \textit{ledged} one, having steps similar to the vicinal surface. We identify the atomic displacements along a misfit dislocation network at the interface leading to the phase transformation. In case of \textit{ledged} interface, stacking faults are nucleated at the steps, which hinder the interface motion, leading to a lower mobility of the inter-phase boundary, than that of flat interface. Interestingly, we also find the temperature dependence of the interface mobility to show opposite trends in case of \textit{flat} vs. \textit{ledged} boundary. We believe that our study is going to present a unified and comprehensive view of martensitic transformation in iron with different interface morphology, which is lacking at present, as \textit{flat} and \textit{ledged} interfaces are treated separately in the existing literature.

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Pawan Kumar Tripathi, Shivraj Karewar, Yu-Chieh Lo, Somnath Bhowmick. 2021-01-19. Role of interface morphology on the martensitic transformation in pure Fe. https://doi.org/10.1016/j.mtla.2021.101085

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