Acta Metallurgica Sinica (English Letters) ›› 2021, Vol. 34 ›› Issue (10): 1375-1385.DOI: 10.1007/s40195-021-01238-w

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Numerical Prediction of Intermetallic Compounds Thickness in Friction Stir Welding of Dissimilar Aluminum/Magnesium Alloys

Chunliang Yang1, Chuansong Wu1(), Junjie Zhao1   

  1. 1MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing, Institute of Materials Joining, Shandong University, Jinan, 250061, China
  • Received:2020-12-24 Revised:2021-01-29 Accepted:2021-02-14 Online:2021-04-22 Published:2021-04-22
  • Contact: Chuansong Wu
  • About author:Chuansong Wu, wucs@sdu.edu.cn

Abstract:

An atomic diffusion model is developed to predict the thickness of intermetallic compounds (IMCs) at the interface of aluminum/magnesium alloys in dissimilar friction stir welding. Both the temperature and the strain rate associated with dislocation density at the checking point are used to determine the diffusion coefficients. The variations of the diffusion coefficients and the thickness of IMCs are quantitatively analyzed at selected characteristic time instants during welding process. It is found that the dislocation density can increase the diffusion coefficient and plays a dominant role in the IMCs formation during the plastic deformation stage. Especially in magnesium alloy and Al12Mg17, the diffusion coefficient is increased by two orders of magnitude or even nearly three orders of magnitude by considering the dislocation density. The temperature is the main influencing factor after the end of plastic deformation. The model is validated by comparing the predicted thickness of IMCs with the experimentally measured results.

Key words: Friction stir welding, Aluminum alloys, Magnesium alloy, Intermetallic compounds, Atomic diffusion, Strain rate