The dual role of coherent twin boundaries in hydrogen embrittlement

被引：206

作者：

Seita, Matteo ^{[1
]}

Hanson, John P. ^{[2
]}

Gradecak, Silvija ^{[1
]}

Demkowicz, Michael J. ^{[1
]}

机构：

[1] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA

[2] MIT, Dept Nucl Sci & Engn, Cambridge, MA 02139 USA

来源：

NATURE COMMUNICATIONS | 2015年 / 6卷

基金：

美国国家科学基金会;

关键词：

CENTERED-CUBIC METALS; DISLOCATION EMISSION ARRANGEMENTS; GRAIN-BOUNDARIES; DEFORMATION PROCESSES; FRACTURE; NICKEL; BEHAVIOR; EQUILIBRIUM; PLASTICITY; INTERFACE;

D O I：

10.1038/ncomms7164

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Hydrogen embrittlement (HE) causes engineering alloys to fracture unexpectedly, often at considerable economic or environmental cost. Inaccurate predictions of component lifetimes arise from inadequate understanding of how alloy microstructure affects HE. Here we investigate hydrogen-assisted fracture of a Ni-base superalloy and identify coherent twin boundaries (CTBs) as the microstructural features most susceptible to crack initiation. This is a surprising result considering the renowned beneficial effect of CTBs on mechanical strength and corrosion resistance of many engineering alloys. Remarkably, we also find that CTBs are resistant to crack propagation, implying that hydrogen-assisted crack initiation and propagation are governed by distinct physical mechanisms in Ni-base alloys. This finding motivates a re-evaluation of current lifetime models in light of the dual role of CTBs. It also indicates new paths to designing materials with HE-resistant microstructures.

引用

页数：6

共 52 条

[1] Fatigue crack initiation in Hastelloy X - the role of boundaries [J].