Catalyst-free synthesis, structural, and mechanical characterization of twinned Mg2B2O5 nanowires

Mg2B2O5 nanowires with (010) twins were synthesized for the first time using a catalyst-free method. The microstructure of the Mg2B2O5 nanowires has been extensively studied by cross-sectional high-resolution transmission electron microscopy. Nanoindentation tests were performed directly on individual nanowires to probe their mechanical properties. It was found that the twinned Mg2B2O5 nanowires achieve comparable hardness but 19% decrease in elastic modulus compared to their bulk counterpart. The elastic softening mechanisms of the Mg2B2O5 nanowires are discussed with reference to their twin defects, size, and surface effects.