A theory for cleavage cracking in the presence of plastic flow

Suo, Zhigang; Shih, C. F.; Varias, A G

doi:10.1016/0956-7151(93)90263-r

Cited by 146 publications

(79 citation statements)

References 21 publications

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“…46,59 Although ductile-phase reinforcement has proven to be less effective under cyclic loading as compared to monotonic loading, it has been demonstrated that fatigue-crack growth resistance can be imparted into brittle materials by the addition of a ductile second phase. 46,59 However, considering the behavior for Al/Al 2 O 3 interfaces, for which cycling usually leads to complete interfacial separation, it may be surprising that inspection of the present fracture surfaces reveals only a limited amount of direct separation of the Cu/Al 2 O 3 interface and instead predominantly ductile § This interpretation is plausible, although there are outstanding mechanics questions as to how the near-crack tip deformation occurs without causing discernable blunting, 52 specifically whether dislocation cell structures can account for this 57 and whether strain-gradient effects can describe it. 58 failure in the Cu bridges (Fig.…”

Section: (3) Mechanisms Of Cyclic Fatigue Crack Advancementioning

confidence: 82%

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers

Kruzic

Marks

Yoshiya

et al. 2002

Journal of the American Ceramic Society

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Interfacial fracture toughness and cyclic fatigue-crack growth properties of joints made from 99.5% pure alumina partial transient-liquid phase bonded using copper/niobium/copper interlayers have been investigated at both room and elevated temperatures, and assessed in terms of interfacial chemistry and microstructure. The mean interfacial fracture toughness, G c , was found to decrease from 39 to 21 J/m 2 as temperature was raised from 25° to 1000°C, with failure primarily at the alumina/niobium interfaces. At room temperature, cyclic fatigue-crack propagation occurred at both the niobium/alumina interface and in the alumina adjacent to the interface, with the fatigue threshold, ∆G TH , ranging from 20 -30 J/m 2 ; the higher threshold values in that range resulted from a predominantly near-interfacial (alumina) crack path. During both fracture and fatigue failure, residual copper at the interface deformed and remained adhered to both sides of the fracture surface, acting as a ductile second phase, while separation of the niobium/alumina interface appeared relatively brittle in both cases. The observed fracture and fatigue behavior is considered in terms of the respective roles of the presence of ductile copper regions at the interface which provide toughening, extrinsic toughening due to grain bridging during crack propagation in the alumina, and the relative crack propagation resistance of each crack path, including the effects of segregation at the interfaces found by Auger spectroscopy.

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Section: (3) Mechanisms Of Cyclic Fatigue Crack Advancementioning

confidence: 82%

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers

Kruzic

Marks

Yoshiya

et al. 2002

Journal of the American Ceramic Society

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“…The possibility of a plastic wake is allowed in both the film and substrate, and the depth of the wake below the interface is denoted by H,. The results derived below apply to either the embedded process zone model (EPZ model) or the Suo, Shih and Varias (1993) model (SSV model) when conditions for steady-state crack advance are met as prescribed in the body of the paper.…”

Section: An Applicationmentioning

confidence: 99%

“…At this point, however, they serve to motivate the rationale for the SSV model. Under the assumption that dislocations emitted at the crack tip play a minimal role in crack propagation for the class of interfaces under study, Suo et al (1993) proposed a model capable of producing the high stresses at the crack tip necessary for atomic separation. They imposed an elastic, plasticity-free strip between the line of the crack and the plastic zone.…”

Section: The Ssv Modelmentioning

confidence: 99%

Nonlinear delamination mechanics for thin films

Wei

Hutchinson

1997

Journal of the Mechanics and Physics of Solids

145

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Delaminationof prestressed thin films on thick substrates is analysed accounting for plastic dissipation in either the substrate or film. Emphasis is on large scale yielding wherein the height of the plastic zone at the propagating interface crack tip is comparable to the film thickness. Such conditions are common for both metal and polymer thin films on elastic substrates or for ceramic coatings on metal substrates when the interface between the film and substrate is reasonably strong. Under large scale yielding, the notion of a thickness-independent interface toughness no longer pertains, and a nonlinear fracture mechanics is required to quantify delamination.Two such approaches are pursued in this paper using models based on the attainment of critical conditions at the interface crack tip within the plastic zone. Steady-state film delamination is analysed for conditions where yielding occurs either in the film or in the substrate, and critical combinations of prestress and thickness are predicted. The theory is applied to a recent set of experiments on copper films delaminating from silica substrates. r{Tj 1997

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“…Thus, 2c pz directly governs G c , the term w p serving only to amplify variations in this local fracture energy. This amplification mechanism has often been referred to as the ''valve'' effect [28,30,31].…”

Section: Introductionmentioning

confidence: 99%

“…Several analytical approaches have been proposed to describe, for instance, cleavage fracture in the presence of plastic flow, fracture in embrittled materials, in composites, and in other materials to point out in various ways the direct relation that exists between the local term 2c pz and the total fracture energy G c [2,[30][31][32][33][34][35][36][37]. This link has also been investigated by numerical analysis, in the ''local'' approach to fracture [38] and using the cohesive zone model (CZM) [39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

Fracture of aluminium reinforced with densely packed ceramic particles: link between the local and the total work of fracture

Miserez

2004

Acta Materialia

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Model composites of pure Al reinforced with 50% ceramic particles are produced by infiltration. The composite fracture energy is measured by J -integral testing. Marked R-curve behaviour is found. The J-R curves exhibit a break in their slope at a well-defined point. This point is shown to denote the onset of macroscopic crack propagation and is used to assess the composite toughness.Toughness reaches values as high as 40 MPa ffiffiffiffi m p . Quantitative metallography and stereoscopic reconstructions of fracture surfaces are used to estimate the local work of fracture in the process zone. The measured (total) fracture energy is about ten times the estimated local fracture energy, for all composites. The main contribution to their total fracture energy is thus from plastic dissipation around the crack-tip; however, the toughness is still dictated by the local fracture energy. This study hence experimentally substantiates the ''valve'' concept in fracture mechanics.

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A theory for cleavage cracking in the presence of plastic flow

Cited by 146 publications

References 21 publications

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers

Nonlinear delamination mechanics for thin films

Fracture of aluminium reinforced with densely packed ceramic particles: link between the local and the total work of fracture

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