Grain boundaries are Brownian ratchets

• 成果类型: Article
• 署名作者: Qiu, Caihao; Punke, Maik; Tian, Yuan; Han, Ying; Wang, Siqi; Su, Yishi; Salvalaglio, Marco; Pan, Xiaoqing; Srolovitz, David J.; Han, Jian
• 署名单位: City University of Hong Kong; Technische Universitat Dresden; University of California System; University of California Irvine; Shanghai Jiao Tong University; Technische Universitat Dresden; University of California System; University of California Irvine; University of Hong Kong; University of Hong Kong
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12847
• DOI: 10.1126/science.adp1516
• 发表日期: 2024-08-30
• 页码: 980-985
• 关键词: electric-current; molecular-dynamics; growth behavior; motion; recrystallization; aluminum; kinetics; mobility; driven; tilt

摘要

We demonstrate that grain boundaries (GBs) behave as Brownian ratchets, exhibiting direction-dependent mobilities and unidirectional motion under oscillatory driving forces or cyclic thermal annealing. We observed these phenomena for nearly all nonsymmetric GBs but not for symmetric ones. Our observations build on molecular dynamics and phase-field crystal simulations for a wide range of GB types and driving forces in both bicrystal and polycrystalline microstructures. We corroborate these simulation results through in situ experimental observations. We analyze these results with a Markov chain model and explore the implications of GB ratchet behavior for materials processing and microstructure tailoring.