The mechanical behavior of nanoscale Al/TiN multilayers with a thickness ratio of 9:1 deposited by reactive sputter deposition, with TiN layer thicknesses of 1-50 nm, has been evaluated. Hardness values measured by nanoindentation methods showed considerably higher hardness than a rule of mixtures estimate, and increasing hardness with decreasing layer thickness. Microstructural analysis has been performed using transmission electron microscopy (TEM) and high-resolution TEM. A dislocation image force model is used to understand the strengthening mechanisms.
Bibliographical noteFunding Information:
This research is funded by DOE, Office of Science, Office of Basic Energy Sciences. The authors would also like to acknowledge the very fruitful discussions with Prof. J.P. Hirth, and Dr. Darrick Williams and J.K. Baldwin for their valuable technical help.