Shearing brittle intermetallics enhances cryogenic strength and ductility of steels

• 成果类型: Article
• 署名作者: Wang, Feng; Song, Miao; Elkot, Mohamed N.; Yao, Ning; Sun, Binhan; Song, Min; Wang, Zhangwei; Raabe, Dierk
• 署名单位: Central South University; Egyptian Knowledge Bank (EKB); Suez University; East China University of Science & Technology
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8762
• DOI: 10.1126/science.ado2919
• 发表日期: 2024-05-31
• 页码: 1017-1022
• 关键词: high-entropy alloy; mechanical-properties; low-temperature; spinodal decomposition; corrosion behavior; tensile properties; impact properties; precipitation; mn; density

摘要

Precipitates are crucial for crafting mechanically strong metallic materials. In this work, we report the dislocation cutting of B2 (ordered body-centered cubic) nanoprecipitates, typically considered nonshearable intermetallics, in a lightweight compositionally complex steel during cryogenic tensile loading. Shearing is enabled by the high strength level for dislocation glide within the austenitic matrix, attributed to the substantial strengthening from subnanoscale local chemical ordering zones and the pronounced solid solution strengthening from the multiprincipal elements in the matrix. This mechanism not only harnesses the intense strengthening and strain hardening provided by otherwise impenetrable brittle nanoprecipitates but also introduces ductility through their sequential shearing with ongoing deformation. Our steel thus showcases ultrahigh cryogenic tensile strength up to 2 gigapascal at a remarkable tensile elongation of 34%. This study reveals a new strategy for designing high-performance structural materials.