MICROSTRUCTURE DESCRIPTION AND MICROMECHANICAL PROPERTIES OF SPRUCE WOOD

The knowledge about the microstructure and morphology of individual phases also allows an artificial modification of the material, or its processing, to produce engineered products with required properties. The purpose of our work was to investigate the distribution of elastic stiffness within the tissues of individual cells using the finest equipment and to observe the morphology of individual phases. A quasi-static nanoindentation was carried out on the cell walls of earlywood and latewood tracheids of spruce wood. The dynamic modulus mapping, also known as nanoDMA, was utilized to obtain the map of elastic moduli over the entire tracheid cross-section. In particular, it was found that the stiffness cells walls is approximately 10.5 GPa and 12.5 GPa in the case of earlywood and latewood tracheids, respectively. The difference between earlywood and latewood elastic stiffness is attributed to a different chemical composition and orientation of fibrils. The acquired data are indispensible for micromechanical modeling and design of engineered products with superior mechanical properties