文献类型：期刊文献

英文题名：Topological passivation makes high strength alloys insensitive to hydrogen embrittlement

作者：Cheng, Huijie[1]; Sun, Binhan[1]; Zhang, Aochen[1]; Ponge, Dirk[2]; Yan, Fengkai[3]; Lu, Tiwen[1]; Zhang, Xian-Cheng[1]; Raabe, Dierk[2]; Tu, Shan-Tung[1]

机构：[1] Key Laboratory of Pressure Systems and Safety, Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China; [2] Max Planck Institute for Sustainable Materials, Max-Planck-Stra?e 1, Düsseldorf, 40237, Germany; [3] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China

年份：2025

外文期刊名：arXiv

收录：EI(收录号：20250551011)

语种：英文

外文关键词：Binary alloys - Chemical attack - Chromium alloys - Cobalt alloys - Cracks - Grain boundaries - High strength alloys - Hydrogen embrittlement - Laminating - Passivation - Strength of materials - Surface reactions - Ternary alloys - Textures - Topology

摘要：Infrastructure parts for a hydrogen (H) economy need alloys that are mechanically strong and at the same time resistant to the most dangerous and abrupt type of failure mode, namely, H embrittlement. These two properties are in fundamental conflict, as increasing strength typically amplifies susceptibility to H-related failure. Here, we introduce a new approach to make alloys resistant to H embrittlement, by creating a topological passivation layer (up to a few hundred micrometers thick) near the material surface, the region that is most vulnerable to H ingress and attack. The approach is fundamentally different from conventional passivation methods against environmental attack which involve surface chemical reactions. In contrast, topological passivation works without chemical modification or coating. It features instead a layer of ultrafine laminated grains with tens of times higher dislocation density than conventional materials, altering H diffusion, trapping and crack evolution. We tested the concept on a face-centered cubic (FCC) CoCrNi medium entropy model alloy which undergoes severe H-induced intergranular cracking. Two key mechanisms create the topological passivation: First, the high density (up to ~1.3×1015 m-2) of H-trapping dislocations within the passivating grain layer decelerates H migration by up to about an order of magnitude, delaying H-induced crack initiation at grain boundaries. More importantly, once unavoidable micro-sized H-induced intergranular cracks emerge in the topmost surface region, they become completely arrested by the laminated grains, due to a transition in the embrittlement mechanism from H-enhanced grain boundary decohesion to highly energy-dissipative dislocation-associated cracking. These effects almost completely eliminate H embrittlement, at even doubled yield strength, when exposing the so architected material to harsh H attack. Our approach leverages surface mechanical treatments to tailor metallic microstructures in surface regions most susceptible to H attack, providing a scalable solution to protect alloys from H-induced damage. Copyright ? 2025, The Authors. All rights reserved.