Twin-assisted precipitation during hot compression of an Mg-Gd-Zn-Zr magnesium alloy

Saadati, Mohammad, Azari Khosroshahi, Rasoul, Ebrahimi, Golamreza et Jahazi, Mohammad. 2017. « Twin-assisted precipitation during hot compression of an Mg-Gd-Zn-Zr magnesium alloy ». Materials Science and Engineering A, vol. 706. pp. 142-152.
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Résumé

Dynamic precipitation in an Mg-Gd-Zn-Zr alloy during hot compression at 350℃ and 450℃ and at strain rates of 0.001-0.1s-1 is investigated. The deformation conditions were designed such as to promote twinning or slip of dislocations. The results indicated that both twinned and non-twinned grains were present at 350℃, with the extent being a function of the applied strain rate. The formation and propagation of {101̅2}〈1̅011〉 primary tensile twins within the twinned grains was identified as being at root of the twin-assisted precipitation phenomenon. The precipitates had spherical-morphology in the twinned grains whereas parallel arrays of rod-shaped precipitates formed in the non-twinned grains due to dynamic precipitation on the slip bands and the stacking faults. Twin-assisted precipitates were suppressed by increases in the strain rate at 350℃ because of the shorter time required for solute element diffusion towards the nucleated precipitates at that temperature. Increasing the deformation temperature to 450℃ changed the dominant deformation mechanism from twinning to slip of dislocations, resulting in the formation of rod-shaped precipitates similar to those observed in non-twinned grains at 350℃. An EBSD analysis was used to study the dominant deformation mechanism as a function of the Schmid factor, and the twinning deformation mechanism was found to be predominant in the grains having a lower Schmid factor.

Type de document:	Article publié dans une revue, révisé par les pairs
Professeur:	Professeur Jahazi, Mohammad
Affiliation:	Génie mécanique
Date de dépôt:	03 nov. 2017 20:09
Dernière modification:	13 avr. 2023 16:08
URI:	https://espace2.etsmtl.ca/id/eprint/15838

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