Heterophase interface-mediated formation of nanotwins and 9R phase in aluminum: Underlying mechanisms and strengthening effect

Release Time:2025-04-30  Hits:

• Date:2025-04-30
• Title of Paper:Heterophase interface-mediated formation of nanotwins and 9R phase in aluminum: Underlying mechanisms and strengthening effect
• Journal:Acta Materialia
• Summary:Nanostructured crystalline Al/amorphous AlN multilayer films with a wide layer thickness (h) range from
  ~10 nm up to ~200 nm were prepared by using magnetron sputtering. Nanotwins and 9R phase were
  substantially observed in the Al layers, showing a strong thickness dependence. The 9R phase pre-
  dominantly penetrated through the Al layer in the II regime of h ? ~20 nm, while mainly terminated
  within the layer interior in the I regime of h > ~20 nm. On the contrary, the coherent nanotwins were
  boosted when h > ~20 nm and the percentage of twinned Al grains was greatly increased. The formation
  mechanisms of 9R phase and coherent nanotwins were discussed in terms of the interfacial chemistry/
  physics modulated by the amorphous AlN layers, which displayed gradient characteristics and hence was
  sensitive to the layer thickness. A significant thickness dependence of hardness was also evident that the
  hardness monotonically increased with reducing h in the I regime, while reached a peak value and hold
  almost unchanged in the II regime. The hardness in the II regime is about 1GPa greater than the pre-
  dictions from an interfacial barrier crossing model. This discrepancy is mainly contributed by the layer-
  penetrating 9R phase rather than the nanotwins. This study provides a new perspective on fabricating
  nanotwinned Al by utilizing heterophase interfaces
• Co-author:J.D. Zuo, C. He, M. Cheng, K. Wu, Y.Q. Wang, J.Y. Zhang , G. Liu , J. Sun
• Volume:174 (2019) 279e288
• Page Number:174 (2019) 279e288
• Translation or Not:No
• Date of Publication:2019-05-29