Damage micromechanisms of stress corrosion cracking in Al-Mg alloy with high magnesium content

Kyosuke Hirayama, Hiroyuki Toda, Dongsheng Fu, Ryohei Masunaga, Hang Su, Kazuyuki Shimizu, Akihisa Takeuchi, Masayuki Uesugi

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Al-10Mg alloys, which are highly susceptible to SCC, were prepared with various β precipitate morphologies. Interrupted in-situ tensile tests were conducted under synchrotron X-ray radiation, employing a recently developed X-ray microtomography technique that combines high-energy, applicability to metallic materials, and ultra-high resolution. Preferential dissolution of the β phase along grain boundaries, and incidental intergranular and transgranular fracture, were observed in 3D. A drastic decrease in SCC resistance was measured after hydrogen charging. The additional effect of external hydrogen absorbed from an aqueous solution during loading was also revealed, by directly measuring crack-tip plasticity. The aquatic environment, one of the most extreme conditions for hydrogen uptake, caused continuous crack-tip corrosion. Catastrophic failure was observed when an alloy had both a relatively high areal grain boundary coverage by film-like β phase, and a reticulately interconnected plate-like β phase in the grain interior. Hydrogen bubble formation was also observed, in relation to the progress of crack-tip corrosion. The main corrosion product was identified as Al(OH)3, based on its linear absorption coefficient. The respective amounts of corrosion products and hydrogen gas in the gas bubbles, and the pH value of the aqueous solution, were accurately measured during in-situ tensile testing, enabling estimation of the local elevation of hydrogen content in the crack-tip vicinity. Finally, a quantitative criterion for the occurrence of hydrogen embrittlement in inter-β ligaments is discussed, together with the applicability of the findings to the prevention of SCC.

Original languageEnglish
Article number109343
JournalCorrosion Science
Publication statusPublished - May 15 2021

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science


Dive into the research topics of 'Damage micromechanisms of stress corrosion cracking in Al-Mg alloy with high magnesium content'. Together they form a unique fingerprint.

Cite this