The Morphology of Fracture Surfaces: A Tool for Understanding Crack Propagation in Complex Materials

2003 ◽  
Vol 10 (05) ◽  
pp. 797-814 ◽  
Author(s):  
Elisabeth Bouchaud
Keyword(s):  
Crack Propagation ◽  
Heterogeneous Materials ◽  
Morphological Parameters ◽  
Complex Materials ◽  
Quantitative Morphology ◽  
Length Scales ◽  
Fracture Surfaces ◽  
Theoretical Developments

We review experiments concerning the quantitative morphology of the fracture surfaces of various materials, at different length scales, using different techniques. These experiments could separate "universal" morphological parameters from material-dependent ones. We show how these results have been at the basis of theoretical developments on crack propagation and damage in heterogeneous materials.

Damage and Crack Propagation at a Microstructural Scale

1999 ◽  
Vol 578 ◽  
Author(s):  
Elisabeth Bouchaud ◽  
Florin Paun ◽  
Elodie Ducourthial
Keyword(s):  
Grain Size ◽  
Quantitative Analysis ◽  
Crack Propagation ◽  
Correlation Length ◽  
Scaling Laws ◽  
The Self ◽  
Metallic Materials ◽  
Strong Correlations ◽  
Length Scales ◽  
Fracture Surfaces

AbstractA quantitative analysis of the morphology of damage cavities in metallic materials is performed. At larger length scales, the self-affine correlation length of fracture surfaces is shown to be correlated to the grain size. These observations suggest a new scenario for the origin of scaling laws observed on fracture surfaces. It is argued that they reflect strong correlations in damage created prior to fracture during crack propagation.

Cleavage Planes of Icosahedral Quasicrystals: A Molecular Dynamics Study

2003 ◽  
Vol 805 ◽  
Author(s):  
Frohmut Rösch ◽  
Christoph Rudhart ◽  
Peter Gumbsch ◽  
Hans-Rainer Trebin
Keyword(s):  
Molecular Dynamics ◽  
Brittle Fracture ◽  
Crack Propagation ◽  
Three Dimensional ◽  
Propagation Direction ◽  
Mode I ◽  
Dynamic Crack ◽  
Fracture Surfaces ◽  
Icosahedral Quasicrystals ◽  
Crack Tip Plasticity

ABSTRACTThe propagation of mode I cracks in a three-dimensional icosahedral model quasicrystal has been studied by molecular dynamics techniques. In particular, the dependence on the plane structure and the influence of clusters have been investigated. Crack propagation was simulated in planes perpendicular to five-, two- and pseudo-twofold axes of the binary icosahedral model.Brittle fracture without any crack tip plasticity is observed. The fracture surfaces turn out to be rough on the scale of the clusters. These are not strictly circumvented, but to some extent cut by the dynamic crack. However, compared to the flat seed cracks the clusters are intersected less frequently. Thus the roughness of the crack surfaces can be attributed to the clusters, whereas the constant average heights of the fracture surfaces reflect the plane structure of the quasicrystal. Furthermore a distinct anisotropy with respect to the in-plane propagation direction is found.

Unstable crack propagation in LAPONITE® gels: selection of a sinusoidal mode in an electric field

RSC Advances ◽  
2016 ◽  
Vol 6 (69) ◽  
pp. 64297-64305 ◽  
Author(s):  
Somasri Hazra ◽  
Sudeshna Sircar ◽  
Tajkera Khatun ◽  
Moutushi Dutta Choudhury ◽  
Abhra Giri ◽  
...  
Keyword(s):  
Electric Field ◽  
Crack Propagation ◽  
Unstable Crack ◽  
Fracture Surfaces ◽  
Selection Of

We report observation of wavy cracks and naturally patterned fracture surfaces in drying LAPONITE® paste.

Scanning Electron Microscope of Fatigue and Creep-Fatigue From Stress Concentrations in Plates

2012 ◽  
Author(s):  
Osamu Watanabe ◽  
Marina Kikuchi ◽  
Akihiro Matsuda
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Scanning Electron Microscope ◽  
Crack Propagation ◽  
Fatigue Test ◽  
304 Stainless Steel ◽  
High Temperature Fatigue ◽  
Fracture Surfaces ◽  
Creep Fatigue ◽  
Scanning Electron

Fatigue crack propagation forms a distinctive pattern which is observable on the fracture surfaces of materials. Purpose of this study is to analyze the fracture process of the materials received under cyclic distortion loading using scanning electron microscope. The test piece made of type 304 stainless steel with the hole of a different size is examined on the conditions of the high temperature fatigue and creep-fatigue. This study first takes a picture of the fracture with SEM, and measures the intervals of striation on fracture surfaces. Next, this study calculates the number of the crack propagation cycles and compares with the original experimental data defined by the load decrease condition or the crack length. Consequently, there is not so much differences at striation intervals regardless of the size of the root notch radius in the present tests. However, the striation spacing in the creep fatigue test has grown about twice of striation intervals in the high temperature fatigue-test.

scholarly journals Fatigue Crack Growth Behavior and Fracture Toughness of EH36 TMCP Steel

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6621
Author(s):  
Qingyan Zhu ◽  
Peng Zhang ◽  
Xingdong Peng ◽  
Ling Yan ◽  
Guanglong Li
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Fracture Surfaces

The fatigue crack growth behavior and fracture toughness of EH36 thermo-mechanical control process (TMCP) steel were investigated by fatigue crack growth rate testing and fracture toughness testing at room temperature. Scanning electron microscopy was used to observe the fracture characteristics of fatigue crack propagation and fracture toughness. The results indicated that the microstructure of EH36 steel is composed of ferrite and pearlite with a small amount of texture. The Paris formula was obtained based on the experimental data, and the value of fracture toughness for EH36 steel was also calculated using the J-integral method. The observations conducted on fatigue fracture surfaces showed that there were a lot of striations, secondary cracks and tearing ridges in the fatigue crack propagation region. Additionally, there existed many dimples on the fracture surfaces of the fracture toughness specimens, which indicated that the crack was propagated through the mechanism of micro-void growth/coalescence. Based on the micromechanical model, the relationship between the micro-fracture surface morphology and the fracture toughness of EH36 steel was established.

scholarly journals Influence of the material substructure on crack propagation: a unified treatment

2005 ◽  
Vol 461 (2054) ◽  
pp. 371-395 ◽  
Author(s):  
Paolo Maria Mariano
Keyword(s):  
Crack Propagation ◽  
Process Zone ◽  
Condensed Matter ◽  
Three Dimensional ◽  
Finite Size ◽  
Coarse Grained ◽  
Complex Materials ◽  
Material Texture ◽  
Strain Gradient Effects ◽  
Gradient Effects

The influence of the material texture (substructure) on the force driving the crack tip in complex materials is analysed in a three–dimensional continuum setting. The theory proposed accounts for finite deformations and general coarse–grained morphological descriptors of the substructure. A modified expression of the J integral is obtained together with other path integrals which are necessary to treat cases in which the process zone around the tip has finite size. They allow also us to consider the influence of the presence of diffused interfaces in multiphase solids on crack propagation. The results can be applied to a very wide class of material substructures occurring in condensed matter. To indicate possible applications, the behaviour of cracks in ferroelectrics and in materials with strain–gradient effects is discussed: the specializations of the general results reduce to expressions that fit reasonably experimental data.

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