Stress corrosion in Mg-Al-Mn alloy discussed with measured stress distributions

Shun ichiro Tanaka, Shuichi Iwata

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

The effect of stress on a corrosion mode of magnesium alloy in an aqueous solution was studied with elucidating the time dependent characteristics of a corrosion product and a concentrated stress value around an artificial notch. Stress values of a thixomolded Mg alloy plate, AM-60, were measured separately in α-Mg and Mgl7Al12 phases using microarea X-ray sin2Ψ method and residual stresses in the lapped plate were about 30 MPa compressive and about 30 MPa tensile, respectively. The concentrated stress in α-Mg, ranged from 100 MPa tensile to 80 MPa compressive ahead the V notch root when loaded by three point bending to KI = 6 MPa·m 1/2 . Corrosion mode of AM-60 in 0.9% NaCl aqueous solution was quite different depending on the sign of the stresses; a fine and dense amorphous hydro-oxide formed in the region of tensile stress whereas a coarse amorphous oxide formed in that of compressive stress. The former reaction product formed in a short time, but the latter grew gradually. Concentrated tensile stress in α-Mg phase at the notch root relaxed within two minutes by the corrosion followed by gradual relaxation of the stress to zero. This phenomenon is considered to be the compensation effect of the lattice spacing in α-Mg phase.

Original languageEnglish
Pages (from-to)283-288
Number of pages6
JournalMaterials Science Forum
Volume350
Publication statusPublished - 2000 Jan 1
Externally publishedYes
EventProceedings of the 1st Nagaoka International Workshop on Magnesium Platform Science and Technology 2000 - Nagaoka, Jpn
Duration: 2000 Jul 272000 Jul 29

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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