Abstract
The solidification of alloys is typically controlled by solute diffusion due to the solute partitioning happening at the solid-liquid interface.
In this study, we show that the switching from solute diffusion-controlled growth to thermal diffusion-controlled growth may happen at the solidification front during rapid solidification processes of alloys, such as additive manufacturing and melt spinning, using a phase-field model. The switching is found to be triggered by the cooling of the solid-liquid interface when it becomes colder than the solidus temperature. The switching introduces a sudden jump of growth velocity, an increase in solute concentration, and the refining of the resulting microstructures. All those changes predicted by the phase-field simulations agree with experimental observations quantitatively. The switching of control mechanisms can be exploited by manipulating the processing conditions to form refined microstructures or layered structures for improved mechanical properties.
Bio
Yijia Gu, Ph.D.
Assistant Professor
Missouri University of Science & Technology
Dr. Yijia Gu is an assistant professor of Materials Science and Engineering at Missouri University of Science and Technology. He earned a Ph.D. in Materials Science and Engineering from Pennsylvania State University in 2014 and further honed his expertise during a four-year tenure at Alcoa Technical Center.
Dr. Gu’s research focuses on unraveling the processing–structure–property relationships in advanced materials using computational tools such as CALPHAD and phase-field modeling. His work spans both functional materials (including ferroelectrics, dielectrics, and optoelectronic materials) and structural materials (such as lightweight high-strength steel and aluminum alloys), with current projects addressing advanced manufacturing, aluminum recycling, and the development of new ferroelectrics for nonvolatile memories.