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<p>Amorphous alumina is hard but brittle like all ceramic type materials which affects durability under impact or scratch. Here we show that alumina layers below 100 nm thickness when stacked with aluminum interlayers exhibit exceptional performances including toughness equal to 300 J.m<sup>−2</sup> determined by on chip nanomechanics. This is almost two orders of magnitude higher than bulk alumina and higher than any other thin hard coatings. In addition, a hardness above 8 GPa combines with a fracture strain above 5%. The origin of this superior set of properties is unravelled via in-situ TEM and mechanical models. The combination of constrained alumina layers with ductile behavior, strong “accommodating” interfaces, giant shear deformability of Al layers, and plasticity-controlled crack shielding cooperate to stabilize deformation, dissipate energy and arrest cracks. These performances unlock several options of applications of Al<sub>2</sub>O<sub>3</sub> in which brittleness under contacts prevents benefiting from remarkable functional properties and chemical stability.</p>

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Al2O3/Al hybrid nanolaminates with superior toughness, strength and ductility

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年2月4日

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  • Paul Baral,
  • Sahar Jaddi,
  • Hui Wang,
  • Andrey Orekhov,
  • Nicolas Gauquelin,
  • Alireza Bagherpour,
  • Frederik Van Loock,
  • Michaël Coulombier,
  • Audrey Favache,
  • Morgan Rusinowicz,
  • Johan Verbeeck,
  • Stéphane Lucas,
  • Jean-Pierre Raskin,
  • Hosni Idrissi,
  • Thomas Pardoen

摘要

Amorphous alumina is hard but brittle like all ceramic type materials which affects durability under impact or scratch. Here we show that alumina layers below 100 nm thickness when stacked with aluminum interlayers exhibit exceptional performances including toughness equal to 300 J.m−2 determined by on chip nanomechanics. This is almost two orders of magnitude higher than bulk alumina and higher than any other thin hard coatings. In addition, a hardness above 8 GPa combines with a fracture strain above 5%. The origin of this superior set of properties is unravelled via in-situ TEM and mechanical models. The combination of constrained alumina layers with ductile behavior, strong “accommodating” interfaces, giant shear deformability of Al layers, and plasticity-controlled crack shielding cooperate to stabilize deformation, dissipate energy and arrest cracks. These performances unlock several options of applications of Al2O3 in which brittleness under contacts prevents benefiting from remarkable functional properties and chemical stability.