Influence of microstructure-driven hydrogen distribution on environmental hydrogen embrittlement of an Al–Cu–Mg alloy

The effect of pre-strain on the hydrogen embrittlement of Nb-free and Nb-added low-carbon steels with ferrite-pearlite structure was investigated in this study. After the steels were electrochemically charged with hydrogen, slow-strain rate tensile (SSRT) tests were conducted on them to examine hydrogen embrittlement behavior. The SSRT test results revealed that the Nb-added steel had a lesser decrease of elongation and reduction of area than the Nb-free steel. The formation of NbC carbide and grain refinement caused by the Nb addition improved resistance to hydrogen embrittlement. The loss of elongation and the reduction of area after hydrogen charging occurs when pre-strain is increased. The pre-strain increases dislocation density and thus increases the amount of reversible hydrogen trap sites associated with hydrogen embrittlement. 10% pre-strained specimens exhibited a significant loss in elongation and reduction of area, regardless of Nb addition. Based on the results of electron back-scatter diffraction, fractographic, and silver decoration analyses for Nb-free and Nb-added steels, the hydrogen embrittlement mechanism in low-carbon steels with different amounts of pre-strain is discussed in terms of dislocation density and hydrogen distribution.

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Effect of Thermomechanical Treatment on Hydrogen Embrittlement and Stress Corrosion Cracking of Al-8%Mg Alloy

Journal of the Japan Institute of Metals and Materials ◽

10.2320/jinstmet1952.45.4_373 ◽

1981 ◽

Vol 45 (4) ◽

pp. 373-378 ◽

Cited By ~ 2

Author(s):

Tadakazu Ohnishi ◽

Kenji Higashi ◽

Yoshizo Nakatani

Keyword(s):

Hydrogen Embrittlement ◽

Stress Corrosion ◽

Thermomechanical Treatment ◽

Stress Corrosion Cracking ◽

Corrosion Cracking ◽

Mg Alloy

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The Analysis of Hydrogen Diffusion under Heat Transfer Condition around the Heat Affected Zone of Welding

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.931 ◽

2004 ◽

Vol 261-263 ◽

pp. 931-936 ◽

Cited By ~ 2

Author(s):

K. Takei ◽

A.Toshimitsu Yokobori Jr.

Keyword(s):

Heat Transfer ◽

Heat Treatment ◽

Numerical Analysis ◽

Hydrogen Embrittlement ◽

Brittle Fracture ◽

Theoretical Analysis ◽

Hydrogen Diffusion ◽

Post Weld Heat Treatment ◽

Hydrogen Distribution ◽

Transfer Condition

Hydrogen embrittlement causes a crack initiation and brittle fracture. Therefore, it is important to conduct theoretical analysis to predict hydrogen distribution on the basis of reasonable physical model. In this paper, numerical analysis on the hydrogen diffusion and concentration at the localized stress field was conducted to clarify the behavior of hydrogen concentration and the sensitivity of hydrogen embrittlement. Furthermore, on the basis of this analysis, the effect of post weld heat treatment on the release of concentrated hydrogen was analyzed and optimum condition of post and pre heat treatment on the welding was investigated.

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