TY - JOUR

T1 - Multi-scale interface design of strong and damage resistant hierarchical nanostructured materials

AU - Daniel, Rostislav

AU - Meindlhumer, Michael

AU - Zalesak, Jakub

AU - Baumegger, Walter

AU - Todt, Juraj

AU - Ziegelwanger, Tobias

AU - Keckes, Julius

AU - Mitterer, Christian

AU - Keckes, Jozef

PY - 2020/11

Y1 - 2020/11

N2 - Synthesis of damage resistant nanostructured materials with high strength and fracture toughness is a challenging task. In this work, multi-scale interfaces were implemented into a hierarchical TiN/SiO x microstructure to mimic stepwise crack growth behaviour of the hard and damage resistant bivalve mollusc Saxidomus purpuratus shell. In situ micromechanical testing in scanning and transmission electron microscopes revealed multi-scale crack deflection events at grain boundaries of individual alternately-tilted TiN crystallites, at kinks of their repeatedly tilted columnar grains as well as crack interaction with perpendicular interfaces of elastic amorphous SiO x layers. These events induced an increase in the crack surface area, reduction of the crack driving force and dissipation of local stress and energy at the crack tip with subsequent crack slow-down or arrest, resulting in fracture toughness exceeding by ~200% the toughness of monolithic TiN nanoceramics. By this perspective biomimetic microstructural design, catastrophic failure of brittle ceramics may be turned into a predictable and controllable process increasing reliability of strong materials in various challenging safety-critical engineering applications. It also shows potential paths for the development of strong and simultaneously tough materials with high mechanical and thermal stability.

AB - Synthesis of damage resistant nanostructured materials with high strength and fracture toughness is a challenging task. In this work, multi-scale interfaces were implemented into a hierarchical TiN/SiO x microstructure to mimic stepwise crack growth behaviour of the hard and damage resistant bivalve mollusc Saxidomus purpuratus shell. In situ micromechanical testing in scanning and transmission electron microscopes revealed multi-scale crack deflection events at grain boundaries of individual alternately-tilted TiN crystallites, at kinks of their repeatedly tilted columnar grains as well as crack interaction with perpendicular interfaces of elastic amorphous SiO x layers. These events induced an increase in the crack surface area, reduction of the crack driving force and dissipation of local stress and energy at the crack tip with subsequent crack slow-down or arrest, resulting in fracture toughness exceeding by ~200% the toughness of monolithic TiN nanoceramics. By this perspective biomimetic microstructural design, catastrophic failure of brittle ceramics may be turned into a predictable and controllable process increasing reliability of strong materials in various challenging safety-critical engineering applications. It also shows potential paths for the development of strong and simultaneously tough materials with high mechanical and thermal stability.

KW - Enhanced fracture toughness

KW - Grain boundary and interface design

KW - Multi-scale microstructure design

KW - Nanostructured hierarchical materials

KW - in-situ micromechanical testing

UR - http://www.scopus.com/inward/record.url?scp=85091928268&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2020.109169

DO - 10.1016/j.matdes.2020.109169

M3 - Article

VL - 196

SP - 1

EP - 11

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - November

M1 - 109169

ER -