Hide/Show Apps

Experimental measurements of interfacial strength at the nanoscale Nanoölçekteki arayüzeylerin kayma dayanimlarininin deneysel olarak ölçülmesi

Nanolayered metals are nanomaterials composed of alternating layers of two metals with layer thicknesses below 1 micron. Nanolayered metals are promising for engineering applications due to their superior properties such as high yield strength, thermal stability and radiation resistance. For the development of stronger nanolayers and for obtaining a better understanding of structure-proprety relationships of these materials, the interfacial strengths of the layers needs to be measured accurately and precisely. Molecular dynamics simulations and experimental measurements indicate that the shear strengths of the interfaces are quite low compared to the yield strength of the layers when the layers are of different crystal structures forming an incoherent interface. However, experimental studies on this subject are very limited and there is very limited information regarding the sample preparation approaches. In this study, details of a method for experimental measurement of shear strength of interfaces are presented. For this purpose, copper-niobium layers were produced by physical vapor deposition, micropillar samples were prepared by focused ion beam, and the samples were subjected to compression tests by means of a nanoindenter. Before the sample production, silicon microcylinders were produced by standard lithography techniques which provided a novel approach for reducing the sample production time and cost and improving the manufacturing repeatability of the samples and results. The shear strength results are consistent with experimental data in the literature and molecular dynamics simulations. The applied method offers an effective approach to measure the adhesion properties of the various engineering coatings as well as the interfacial strength of the phase interfaces of multi-phase alloys.