Invited Speaker
Prof. Lei Wang
State Key Laboratory of Solidification Processing,Northwestern Polytechnical University, China
Speech Title: Controlling Solid-liquid Interfacial Energy Anisotropy through the Isotropic Liquid
Abstract: Although the anisotropy of the solid-liquid interfacial free energy for most alloy systems is very small, it plays a crucial role in the growth rate, morphology and crystallographic growth direction of dendrites. Previous work posited a dendrite orientation transition via compositional additions. In this work we examine experimentally the change in dendrite growth behaviour in the Al-Sm (Samarium) system as a function of solute concentration and study its interfacial properties using molecular dynamics simulations. We observe a dendrite growth direction which changes from \(\langle 100\rangle\) to \(\langle 110\rangle\) as Sm content increases. The observed change in dendrite orientation is consistent with the simulation results for the variation of the interfacial free energy anisotropy and thus provides definitive confirmation of a conjecture in previous works. In addition, our results provide physical insight into the atomic structural origin of the concentration dependent anisotropy, and deepen our fundamental understanding of solid-liquid interfaces in binary alloys.
Keywords: Dendrite orientation transition, solid-liquid interface, anisotropy, binary alloys
Biography: Professor Lei Wang is from Northwestern Polytechnical University. He obtained his Bachelor’s (2011), Master’s (2014), and Ph.D. (2017) degrees from Northwestern Polytechnical University. During his doctoral studies, he was a visiting scholar at McGill University, Canada (2015–2016). He subsequently held postdoctoral positions at the University of British Columbia, Canada, the Max Planck Institute for Iron Research, Germany, the Federal Institute for Materials Research and Testing (BAM), Germany, and École Polytechnique, France (2018–2022). His research employs mesoscale numerical simulations, particularly the phase-field method, to study microstructural evolution and the formation mechanisms of metallurgical defects during solidification and processing. He has led or participated in over five national scientific projects and has authored more than 30 SCI-indexed publications, including first-author or corresponding-author papers in Acta Materialia and Nature Communications. He is a recipient of the National Science Fund for Excellent Young Scholars (Overseas), and has been honored as an “Aoxiang Overseas Scholar” by NPU and with the Shaanxi Province Outstanding Doctoral Dissertation Award.