Effect of Split Sleeve Cold Expansion on the Residual Stress, Texture and Fatigue Life of Rolled AZ31B Magnesium Alloy

  • S. Faghih
  • S. K. ShahaEmail author
  • S. B. Behravesh
  • H. Jahed
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


In this study, the feasibility of the split sleeve cold expansion of a wrought magnesium alloy was investigated. The process includes radial expansion of the hole at room temperature, in which magnesium alloys exhibit limited formability. The process has been successfully introduced in the rolled AZ31B Mg sheet, and a preliminary evaluation of fatigue performance showed a significant improvement for the cold expanded hole compared to that of the starting condition. The microstructural analysis shows that microstructure near the hole is accommodating expansion through texture evolution and grain refinements (i.e. elongated grains). The aggressive formation of twins within the grains near the hole surface is believed to be the main hardening mechanism in the very recent vicinity of the notch, where the maximum hardness was achieved. This mechanism alongside the compressive residual stress induced by the cold expansion process delayed crack initiation and suppressed crack propagation leading to high fatigue lives.


Cold expansion Magnesium alloys Characterization Texture AZ31-B 


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Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • S. Faghih
    • 1
  • S. K. Shaha
    • 1
    Email author
  • S. B. Behravesh
    • 1
  • H. Jahed
    • 1
  1. 1.Department of Mechanical & Mechatronics EngineeringUniversity of WaterlooWaterlooCanada

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