Fracture Toughness Enhancement Due to Particle Transformation

1991 ◽  
pp. 125-145
Author(s):  
Zhanjun Gao ◽  
Toshio Mura
Keyword(s):  
Fracture Toughness ◽  
Toughness Enhancement

Fracture Toughness Enhancement of UV-Cured Epoxy Coatings Containing Al2 O3 Nanoparticles

2013 ◽  
Vol 298 (11) ◽  
pp. 1184-1189 ◽  
Author(s):  
Marco Sangermano ◽  
Mohamed Naguib ◽  
Massimo Messori
Keyword(s):  
Fracture Toughness ◽  
Epoxy Coatings ◽  
Toughness Enhancement

Fracture toughness enhancement of brittle nanostructured materials by spatial heterogeneity: A micromechanical proof for CrN/Cr and TiN/SiOx multilayers

2016 ◽  
Vol 104 ◽  
pp. 227-234 ◽  
Author(s):  
Rostislav Daniel ◽  
Michael Meindlhumer ◽  
Jakub Zalesak ◽  
Bernhard Sartory ◽  
Angelika Zeilinger ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Spatial Heterogeneity ◽  
Nanostructured Materials ◽  
Toughness Enhancement

Fracture toughness enhancement of epoxy resin reinforced with graphene nanoplatelets and carbon nanotubes

2020 ◽  
Vol 37 (11) ◽  
pp. 2075-2083
Author(s):  
Shan-Shan Yao ◽  
Chun-Liu Ma ◽  
Fan-Long Jin ◽  
Soo-Jin Park
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Epoxy Resin ◽  
Graphene Nanoplatelets ◽  
Toughness Enhancement

scholarly journals Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Y. L. Chen ◽  
B. Liu ◽  
Y. Huang ◽  
K. C. Hwang
Keyword(s):  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Ceramic Matrix Composites ◽  
Short Fiber ◽  
Matrix Composites ◽  
Reinforced Composites ◽  
Soft Matrix ◽  
Bond Density ◽  
Pull Out ◽  
Toughness Enhancement

Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely lead to the better fracture toughness of these composites, and the optimal interfacial chemical bond density is that making the failure mode just in the transition from CNT pull-out to CNT break. For hard matrix composites, the fracture toughness of composites with weak interfaces can be improved effectively by increasing the CNT length. However, for soft matrix composite, the fracture toughness improvement due to the reinforcing CNTs quickly becomes saturated with an increase in CNT length. The proposed theoretical model is also applicable to short fiber-reinforced composites.

TOUGHENING OF BORON CARBIDE COMPOSITES BY HIERARCHICAL MICROSTRUCTURING

2021 ◽  
Author(s):  
JINGYAO DAI ◽  
EVAN PINEDA ◽  
BRETT BEDNARCYK ◽  
JOGENDER SINGH ◽  
NAMIKO YAMAMOTO
Keyword(s):  
Fracture Toughness ◽  
Boron Carbide ◽  
Bending Test ◽  
Toughening Mechanisms ◽  
Hierarchical Microstructure ◽  
Micro Scale ◽  
Four Point Bending ◽  
Micromechanics Modeling ◽  
Toughness Enhancement ◽  
Micro Indentation

Due to a unique combination of properties including high hardness, low density, chemical and thermal stability, semi-conductivity, and high neutron absorption, boron carbide (B C) is a potential candidate for various applications involving extreme environment. However, B C’s current application is limited because of its low fracture toughness. In this study, a hierarchical microstructure design with features including TiB grains and graphite platelets was used to toughen B C by simultaneously utilizing multiple toughening mechanisms including crack deflection, bridging, and micro-crack toughening. Using field-assisted sintering technology (FAST), B C composites with dense and hierarchical microstructure were fabricated. Previously, the fracture toughness of fabricated B C composites was measured at micro-scale using micro- indentation to have up to 56% improvement. In this work, the B C composites’ fracture toughness was characterized at macro-scale using four-point bending methods and compared with previous results obtained at micro-scale. Micromechanics modeling of fracture behaviors for B C-TiB composites was also performed to evaluate the contributions from experimentally observed toughening mechanisms. From four-point bending tests, B C composites reinforced with both TiB grains (~15 vol%) and graphite platelets (~8.7 vol%) exhibited the highest fracture toughness enhancement from 2.38 to 3.65 MPa·m1/2. The measured values were lower than those obtained using micro- indentation but maintained the general trends. The discrepancy between the indentation and four-point bending test results originated from the complex deformation behaviors triggered by the high contact load during indentation tests. Through micromechanics modeling, introduced thermal residual stress due to thermal expansion mismatch between B C and TiB , and weak interphases at B C-TiB boundaries were identified as the main causes for experimentally observed toughness enhancement. These results proved the effectiveness of hierarchical microstructure designs for B4C toughening and can provide reference for the future design of B4C composites with optimized microstructures for further fracture toughness enhancement.

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