材料科学
脆化
表面应力
脆性
断裂(地质)
范德瓦尔斯力
变形(气象学)
氢脆
位错
复合材料
表面能
冶金
压力(语言学)
化学
腐蚀
语言学
分子
哲学
有机化学
作者
Anirudh Udupa,Tatsuya Sugihara,Koushik Viswanathan,R. M. Latanision,Srinivasan Chandrasekar
出处
期刊:Nano Letters
[American Chemical Society]
日期:2021-11-02
卷期号:21 (22): 9502-9508
被引量:6
标识
DOI:10.1021/acs.nanolett.1c02887
摘要
Environment-assisted fracture phenomena in metals are usually associated with surface energy reduction due to an adsorbed film. Here we demonstrate a unique embrittlement effect in Al that is instead mediated by surface stress, induced by an adsorbed organic monolayer. Atomistic simulations show that the adsorbate carbon-chain length lc controls the surface stress via van der Waals forces, being compressive for lc < 8 and tensile otherwise. For lc > 8, we demonstrate experimentally that the nanoscale film causes a ductile-to-brittle transition on the macroscale. Concomitant with this transition is a nearly 85% reduction in deformation forces. Additional simulations reveal that the microscopic mechanism for the embrittlement is via suppression of dislocation emission at incipient crack-tips. In addition to challenging long-held views on environment-assisted fracture, our findings pertaining to surface-stress induced embrittlement suggest profitable utility in manufacturing processes such as machining and comminution.
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