Evolution of the Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Sheets during Multi-Pass Lowered-Temperature Rolling

Qing Miao , Lantao Zhu (1) , Wenke Wang (1) , Zhihao Wang (2, 3) , Bin Shao (1) , Wenzhen Chen (1) , Yang Yu (1) , Wencong Zhang (1)

1 HIT - Harbin Institute of Technology
2 INSA Rennes - Institut National des Sciences Appliquées - Rennes
3 LGCGM - Laboratoire de Génie Civil et Génie Mécanique

AZ31 magnesium alloy sheets with 2 mm thickness were successfully fabricated by multi-pass lowered-temperature rolling. The evolution of the microstructure, texture, and mechanical properties during the rolling process was investigated. Based on the effect of multiple dynamic recrystallization, multi-pass lowered-temperature rolling not only refined the grain size obviously but also markedly improved the microstructure homogeneity. The resulting sheets had the optimal microstructure morphology with an average grain size of 4.38 mu m. For the texture evolution, the stress state of the rolling process made the (0002) basal plane gradually rotate toward the rolling plane. However, the activation of non-basal slips due to the higher rolling temperature slightly rotated the (0002) basal plane point to the rolling direction (RD). As a result, the grain refinement strengthening and the texture strengthening together increased the yield stress to 202 MPa in the transverse direction (TD) and 189.8 MPa in the RD. Importantly, the resulting sheet concurrently exhibited excellent fracture elongation, about 38% in the TD and 39.2% in the RD. This was mainly ascribed to the finer grain size, giving rise to a significant effect of grain boundary sliding and the activation amount of non-basal slips.

Mots clés: magnesium alloy; dynamic recrystallization; grain size; texture; elongation

Domaines: Sciences de l'ingénieur [physics]

Qing Miao, Lantao Zhu, Wenke Wang, Zhihao Wang, Bin Shao, et al.. Evolution of the Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Sheets during Multi-Pass Lowered-Temperature Rolling. Metals, 2022, 12 (11), pp.1811. ⟨10.3390/met12111811⟩. ⟨hal-03885349⟩