Constitutive and fracture behavior of ultra-strong supercrystalline nanocomposites

Supercrystalline nanocomposites are a new class of hybrid and nanostructured materials that can reach exceptional mechanical strength be fabricated at low temperatures. Hierarchically arranged, they bridge the gap from nano- to macro-scale. Even though their properties starting characterized, constitutive behavior is still largely unexplored. Here, supercrystalline iron oxide nanoparticles, surface-functionalized with oleic acid oleyl phosphate ligands, investigated in both bending compression, loading–unloading tests. A bar geometry implemented better detect deformation prior unstable crack propagation, notched bars tested evaluate fracture toughness. Micro-mechanical tests result values elastic modulus extremely high for supercrystals, reaching record-high numbers acid-based nanocomposites, which also show significant tension–compression asymmetry. The predominantly linear elastic, some more marked nonlinearities arising phosphate-based nanocomposites. toughness types ∼0.3 MPa√m, suggests extrinsic toughening, associated material composition nanostructure, plays an important role. Fractographic observations reveal analogies shear cleavage atomic crystals. influence composition, processing method on analyzed.