Indentation Fracture Response of Al–TiN Nanolaminates

Abstract

Supplementary Material Available OnlineIndentation fracture experiments on aluminium-titanium nitride nanolaminates were conducted both inside and outside of a scanning electron microscope (SEM). Remarkably, indentation fracture toughness increases with increasing strength for bilayer thicknesses less than 10 nm. In addition, slower strain rates favour formation of lateral cracking while increasing rates favour formation of radial cracks. SEM movies show that an increase in radial crack length does not occur during the unloading cycle; this is due to flow of aluminium into the cracks during unloading and is a form of self-healing which should be applicable to metal-ceramic nanolaminates in general.

Mechanical behavior of Cu/TiN multilayers at ambient and elevated temperatures: Stress-assisted diffusion of Cu

“…This demonstrates the ability of the copper to fill cracks and voids in the multilayer film, which could be utilized as a method of moderating/repairing damage acquired at ambient temperature using elevated temperature treatments. At elevated temperatures, this behavior might be termed as dynamic 'self-repairing' of the material [25]. From the perspective of contact metallurgy of Cu interconnects in microelectronic devices, where TiN layers act as barriers to diffusion of Cu into Si or SiO 2 substrates at elevated temperatures, the possibility of micro-forming for integration of devices by the stress-assisted diffusion of copper is promising.…”

“…These materials display a remarkable combination of properties: high strength, significant formability, high work hardening and increasing indentation fracture toughness at small layer thicknesses [17,25]. Thus far, investigations into this class of multilayer have been limited to ambient temperature.…”

In situ Nanoindentation Study of Plastic Co-deformation in Al-TiN Nanocomposites

“…Metal/ceramic layered composites have been fabricated and extensively tested under various types of loading including compression 9 10 11 12 13 , tension 14 and nanoindentation 15 16 17 18 normal to the interface. Most of these studies show that the metallic layer undergoes plastic deformation while the ceramic layer remains in the elastic regime until it fractures.…”

In-situ TEM Study of Dislocation-Interface Interactions

“…By combining the two constitutes into a composite, the stronger constitute strengthens the composites while the ductile constitute make the composites ductile. In general, the mechanical properties of such composites have a low strength than the stronger constitute and a low ductility than the ductile constitute [118][119][120][121][122][123][124][125][126][127][128][129][130][131][132]. Ceramics are lacking in room temperature plasticity and fracture toughness [118,119], although localized dislocation activity in ceramics at room temperature has been observed underneath the indenter [120][121][122].…”