Atomic faulting induced exceptional cryogenic strain hardening in gradient cell-structured alloy

• 成果类型: Article
• 署名作者: Pan, Qingsong; Yang, Muxin; Feng, Rui; Chuang, Andrew Chihpin; An, Ke; Liaw, Peter K.; Wu, Xiaolei; Tao, Nairong; Lu, Lei
• 署名单位: Chinese Academy of Sciences; Institute of Metal Research, CAS; Chinese Academy of Sciences; United States Department of Energy (DOE); Oak Ridge National Laboratory; United States Department of Energy (DOE); Argonne National Laboratory; University of Tennessee System; University of Tennessee Knoxville
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-9843
• DOI: 10.1126/science.adj3974
• 发表日期: 2023-10-13
• 页码: 185-190
• 关键词: high-entropy alloy; strength-ductility synergy; deformation mechanism; superior strength; BEHAVIOR; microstructure; dislocations; toughness; crystals

摘要

Coarse-grained materials are widely accepted to display the highest strain hardening and the best tensile ductility. We experimentally report an attractive strain hardening rate throughout the deformation stage at 77 kelvin in a stable single-phase alloy with gradient dislocation cells that even surpasses its coarse-grained counterparts. Contrary to conventional understanding, the exceptional strain hardening arises from a distinctive dynamic structural refinement mechanism facilitated by the emission and motion of massive multiorientational tiny stacking faults (planar defects), which are fundamentally distinct from the traditional linear dislocation-mediated deformation. The dominance of atomic-scale planar deformation faulting in plastic deformation introduces a different approach for strengthening and hardening metallic materials, offering promising properties and potential applications.