Superplastic deformation behavior of fine-grained AZ80 magnesium alloy prepared by friction stir processing

• Main Authors: Wen Wang, Peng Han, Pai Peng, Hongju Guo, Liying Huang, Ke Qiao, Minna Hai, Qi Yang, Hongduo Wang, Kuaishe Wang, Liqiang Wang
• Format: Article
• Language: English
• Published: Elsevier 2020-05-01
• Series: Journal of Materials Research and Technology
• Subjects: Friction stir processing; Magnesium alloy; Microstructure; Superplasticity; Grain refinement
• Online Access: http://www.sciencedirect.com/science/article/pii/S2238785419316965

Friction stir processing (FSP) is a new severe plastic deformation technique where microstructure refinement, homogenization, and densification occur simultaneously. In this study, the microstructure and superplastic deformation behavior of AZ80 magnesium alloy prepared by FSP were investigated. FSP led to remarkable grain refinement and modification of texture for AZ80 magnesium alloy. A maximum elongation of 606% was obtained at 3 × 10−4 s−1 and 350 ℃. When superplastic deformation was conducted at 3 × 10-3 s−1 and 300 ℃, or at 1 × 10-4 s−1 and 400 ℃, the superplasticity was relatively lower, thus exhibiting a lower strain rate sensitivity. The coarsening of both grains and β-Mg17Al12 precipitates deteriorated superplastic elongation. Applied deformation promoted the premature dissolution of β precipitates at 400 ℃ during superplastic deformation. Moreover, superplastic deformation weakened and spread the basal texture. Although the activation of prismatic and pyramidal slips is beneficial for superplastic deformation, grain boundary sliding is the main superplastic deformation mechanism.