Mechanical property enhancement in laminates through control of morphology and crystal orientation

This article shows the successful implementation of biological design principles into synthetic laminate materials in order to enhance their mechanical properties. We demonstrate and provide a strategy for laminate thin films, which reveals that the control of local crystal anisotropy across laminates together with the optimized layered arrangement are essential for their mechanical behavior. By the example of a laminate consisting of brittle CrN and ductile Cr layers, enhanced material properties are achieved by taking advantage of the self assembly mechanisms of the heterogeneous material during film growth. The usage of local microstructure analysis by a synchrotron based technique as well as miniature mechanical tests allow to understand the relationship between the apparent local microstructure and the accompanied mechanical properties. A crystallographic orientation relationship between Cr and CrN is elucidated, which leads to decisive mechanical enhancement due to microstructural benefits in terms of texture. This results in enhanced strength and fracture toughness of the laminate compared to its single constituents. The systematic approach gives an insight into the complex coherences of laminate materials, where the used techniques and design principles are universally applicable. (paper)