Speaker and Affliation:
Prof. Melis Serofoglu
Marmara University, Turkey
Prof. Melis Serofoglu is presently an Associate professor at the department of Metallurgical and Materials Engineering at the Marmara University, Turkey. She did her B.S. from the department of Metallurgical and Materials Engineering, METU (Ankara, Turkey). Thereafter, she received her PhD. from the Iowa state University (AMES lab), in Materials Science and Engineering, followed by a post-doc at CNRS - UPMC, Paris Nanoscience Institute (INSP), Paris, FRANCE, where she worked on a project with the French space agency. Prof. Serofoglu experience lies in conducting controlled in-situ solidification experiments and studying spontaneous pattern formation/microstructure evolution in multi-phase systems.
27th April, 2022 (Wednesday), 02:00 PM (India Standard Time)
The cooperative or diffusively coupled growth of multiple phases during solidification is one of the most widely observed and generally important classes of phase transformations in materials. Technologically, due to having lower melting points compared with their pure components, and small freezing ranges, these alloys have excellent fluidity exhibited during casting and favorable properties offered by the fine composite structures both of which contribute to the wide application of eutectic alloys in the casting, welding, soldering, and additive manufacturing of engineered components. Academically, the topic of eutectic solidification offers a wealth of rich problems involving multicomponent thermodynamics, solid-liquid and solid-solid interfacial phenomena, morphological stability, chemical and thermal diffusion, and nucleation phenomena. Surprisingly, despite the broad-based technological and academic importance, many fundamental questions regarding eutectic solidification remain unanswered. This lack of understanding severely limits our ability to employ computational methods in the prediction of microstructure for the effective design of new materials and processing techniques through simulation.
In this study, we address critical questions regarding microstructure selection in three-phase eutectic systems in the presence of crystal/crystal anisotropy. Real-time directional solidification and rotating directional solidification experiments were performed on In-Bi-Sn model alloy to characterize different grain types in three-phase systems. It is shown that while lamellar ABAC pattern is preserved during RDS of an isotropic eutectic grain, both the phase arrangement and the morphologies of phases could be altered in the presence of interphase boundary anisotropy. Diverse classes of three-phase eutectic grains are identified and analyzed. It is shown that the formation of these grains is a function of the intrinsic properties of the interphase boundaries, rather than experimental parameters. The equilibrium shapes of the interphase boundaries are experimentally determined and consequently, the corresponding γ- plots of the interphase boundaries are constructed. These results are significant not only for the materials science community but also for the out of equilibrium pattern formation dynamics branch of nonlinear physics.