A new deformation micromechanism operating in the carbon cathode for aluminum electrolysis termed a ripplocation has been proposed in this paper. The creep deformation of semi-graphitic cathode was measured using a modified Rapoport equipment at 965 °C with cryolite ratio = 4.0. The characteristic of the defect was obtained by analyzing TEM photograph of the carbon cathode with different testing times. The results indicated that basal dislocations, bulk ripplocations, kink bands and delamination cracks appeared in succession in the first two stages of the creep deformation. Ripplocations in the carbon cathode make a layer of carbon atoms to glide relative to each other without damaging the in-plane bonds. Ripplocations could also attract each other and result in kink boundaries. The creep strain of the carbon cathode could be accommodated by kink band and delamination cracks during aluminum electrolysis. A more comprehensive understanding of their micromechanics behaviors is very important and could deeply influence our current knowledge of the deformation mechanism of the carbon cathode for aluminum electrolysis.

Ripplocations, kink bands and delamination cracks in carbon cathode materials
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials and chemicals
        2.2 Compressive creep tests
        2.3 Characterization
    3 Results and discussion
        3.1 Creep deformation measurement
        3.2 TEM observation: the microstructures in the carbon cathode
        3.3 Creep mechanism of the carbon cathode
    4 Conclusion
    Acknowledgements 
    References

• Wei Wang(College of Materials Science and Engineering, Henan University of Science and Technology/Collaborative Innovation Center of Nonferrous Metals Henan Province/Henan Key Laboratory of Non-Ferrous Materials Science and Processing Technology)
• Weijie Chen(College of Materials Science and Engineering, Henan University of Science and Technology/Collaborative Innovation Center of Nonferrous Metals Henan Province)
• Haitao Liu(College of Materials Science and Engineering, Henan University of Science and Technology/Collaborative Innovation Center of Nonferrous Metals Henan Province/Henan Key Laboratory of Non-Ferrous Materials Science and Processing Technology)
• Hongtao Zhang(Collaborative Innovation Center of Nonferrous Metals Henan Province)