An analysis of island-delamination type cracking pattern in the brittle film coated on a disk under axisymmetric tension

Nakasa, Keijiro; Takata, Soichiro; Ichigo, Hirozo

doi:10.1016/s0013-7944(97)00097-0

Cited by 13 publications

(6 citation statements)

References 6 publications

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“…Disk specimens with diameter of 190mm and thickness of 1mm were used for biaxial tensile test [7] To ascertain whether the model is valid or not, the crack lengths or the distances between cracks at each pressure were measured by line-cutting method on the photograph.…”

Section: Experimental Methodsmentioning

confidence: 99%

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An Analysis of Repeating-Division Type Cracking Pattern in Brittle Coating under Equi-Biaxial Tension

Gao

Nakasa

Kato

2000

Journal of the Society of Materials Science, Japan

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In order to characterize the "Repeating-division type" cracking pattern which is often observed in the brittle coating on a ductile substrate under equi-biaxial tension, the bulge tests were carried out on steel disks with WC-Co coating which was deposited by high-velocity flame spraying. Moreover, an elastic-plastic analysis was applied to the division process of coating to derive the relation among crack interval, tensile stress and strain of substrate at the division, coating and substrate thickness, strength of coating, interfacial strength between coating and substrate, and material's constants. The characteristics of the division process calculated from the analytical equation agree semiquantitatively well with the experimental results that the crack interval decreases with increasing tensile stress and increases with increasing coating thickness.

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Section: Experimental Methodsmentioning

confidence: 99%

“…The second is "Island-delamination type" [7], where ideally the hexagonal-network cracking appears on the coating and the delamination occurs just after the accomplishment of network cracking. This type of pattern is observed when the interfacial strength is not so high.…”

Section: Introductionmentioning

confidence: 99%

An Analysis of Repeating-Division Type Cracking Pattern in Brittle Coating under Equi-Biaxial Tension

Gao

Nakasa

Kato

2000

Journal of the Society of Materials Science, Japan

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“…As a special case, if the shear strength of the interface is small, the delamination along the interface takes place just after cracking in the coating, i.e. the "Island-delamination type" cracking [6] appears under equi-biaxial tension. In this case, only the first division of the coating results in the delamination and the size of the island L 0 (=L x =L y ) as well as the strain in the substrate at delamination 2 (= x2 = y2 ) can be predicted by using Eqs.3, 5, 6 and 7.…”

Section: Cracking and Delamination Conditions Of The Coatingmentioning

confidence: 99%

Analysis and Simulation of Cracking Patterns in Ceramics Coating under Thermal Stress

Gao

Nakasa

2003

KEM

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Cracking patterns in ceramics coating under thermal stress are analyzed and simulated by "Analysis/FEM Strain Accommodation Method". This method combines the strain of a coated structure obtained from thermal-elastic analysis with the strain of substrate from Finite Element Method (FEM). The computer simulation of cracking patterns consists of random distribution of coating strength and interfacial strength, discrimination of cracking patterns, FEM analysis of strain in substrate, calculation of crack size from theoretical equation, crack initiation, propagation and connection. The method will be very effective not only to estimate the strengths of coating and interface but also to predict where and when the cracking or delamination occurs in coated structures with complex shapes under thermal stress.

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“…(Evans et al, 1983;Hirsch and Mayr, 1988;Kung, 1990;Teixeira, 2001). A similar multi-directional inter-connected network is formed when a multi-axial mechanical loading is applied to the substrate (Andersons et al, 2003), such as the hexagonal crack pattern (called ''island-delamination'') reported in ceramic films plasma-sprayed on a ductile specimen submitted to equi-biaxial tensile tests (Nakasa et al, 1998). On the opposite, when a layered material is subjected to a uniaxial loading (e.g.…”

Section: Introductionmentioning

confidence: 99%

Effect of local stress on the heat-checking morphology in high temperature tool steels under thermal fatigue: Transition from multi-axiality to uniaxiality

Farid¹,

Roux²,

Dour³

et al. 2014

Mechanics of Materials

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To cite this version:Farid Medjedoub, Sabine Le Roux, Gilles Dour, Farhad Rezai-Aria. Effect of local stress on the heat-checking morphology in high temperature tool steels under thermal fatigue: Transition from multi-axiality to uniaxiality. Mechanics of Materials, Elsevier, 2014, 69 (1), p. a b s t r a c tThermal fatigue experiments are performed on a high temperature tool steel X38CrMoV5 (AISI H11), under various maximum temperatures and heating rates. A microscopic interconnected crack pattern (named ''heat-checking'') forms on the oxidised surface of the laboratory tubular specimen. A gradual transition is observed, from a ''cell-type'' cracking at the centre of the specimen to a ''parallel cracking'' at its extremities. This variation of the morphology is well demonstrated by geometrical and topological characteristics of the crack network (micro-crack orientations, cell shape and node density), which change along the longitudinal axis of the specimen. The thermo-elasto-plastic loading of the specimen is estimated by Finite Element Calculations using ABAQUS™. Whatever the thermal fatigue conditions, a linear correlation can be established between the longitudinal and hoop stress amplitude ratio Dr zz /Dr hh and the hoop and longitudinal inter-crack spacing ratio d hh /d zz . It is shown that a stress amplitude ratio close to 1 results in a multi-axial heat-checking, while a uni-axial cracking is generated when Dr zz /Dr hh is close to or below 0.6. This means that the morphology of the heat-checking pattern (cell or parallel type) can be used as an indicator for the local stress ratio of the thermal fatigue specimen or industrial real tools. Fig. 1. (a) Geometry of the TF specimen; (b) instrumented dummy specimen with 28 K-thermocouples spot-welded on the external surface and eight thermocouples brazed in depth.

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An analysis of island-delamination type cracking pattern in the brittle film coated on a disk under axisymmetric tension

Cited by 13 publications

References 6 publications

An Analysis of Repeating-Division Type Cracking Pattern in Brittle Coating under Equi-Biaxial Tension

An Analysis of Repeating-Division Type Cracking Pattern in Brittle Coating under Equi-Biaxial Tension

Analysis and Simulation of Cracking Patterns in Ceramics Coating under Thermal Stress

Effect of local stress on the heat-checking morphology in high temperature tool steels under thermal fatigue: Transition from multi-axiality to uniaxiality

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