Fracture properties of interfacially doped Nb-Al2O3 bicrystals: II, relation of interfacial bonding, chemistry and local plasticity

Cannon, R. M.; Korn, D.; Elssner, G.; Rühle, M.

doi:10.1016/s1359-6454(02)00194-5

Cited by 29 publications

(26 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While prior experience has shown that for coarse grained or single crystal niobium the estimate of H V /3 can lead to an overestimation of the yield stress and an underestimation of the plastic-zone size, 18,19 this hardness exceeds that expected for other diffusion bonded samples and the high yield stress may be one cause of the low interfacial toughness found here.…”

Section: E′contrasting

confidence: 58%

“…Thus, diffusion bonding at 1300-1400°C, accomplished with very flat and clean bonding surfaces under UHV conditions, has yielded interfaces with fracture energies of 90 J/m 2 using 99.9% pure Nb. 18,19 Possible explanations for the lower toughness in the present case may be a much higher yield strength for the present polycrystalline niobium due to impurity uptake during bonding and/or a decrease in the work of attraction, W at , due to copper adsorbed at the interface allowing interface failure at lower toughness values.…”

Section: 38mentioning

confidence: 83%

“…18,19,42 While the strain rate sensitivity of niobium is expected to play a role in reducing deformation during fast fracture, no evidence of deformation was found at the critical fracture initiation point where the loading rate was moderate and more deformation should be expected.…”

Section: 38mentioning

confidence: 99%

“…All these values are markedly higher than found after UHV diffusion bonding using cleaner Nb single crystals at 1400°C. 18,19 Using the classical relation…”

Section: E′mentioning

confidence: 99%

See 3 more Smart Citations

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

View full text Add to dashboard Cite

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.

show abstract

Section: E′contrasting

confidence: 58%

Section: 38mentioning

confidence: 83%

Section: 38mentioning

confidence: 99%

“…All these values are markedly higher than found after UHV diffusion bonding using cleaner Nb single crystals at 1400°C. 18,19 Using the classical relation…”

Section: E′mentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

show abstract

“…Dimple formation between two decohered interfaces must therefore contribute the majority of the local work of fracture for this system. Such interfacial embrittlement effects were explained by Rice and Wang [82] and are receiving increasing attention for grainboundary fracture [34] or for fracture along metal/ ceramic interfaces [83][84][85].…”

Section: Microstructural Dependence Of Fracture and Toughening In Thementioning

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

View full text Add to dashboard Cite

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.

show abstract

Multiscale Simulation of Metal/Ceramic Interface Fracture

Siddiq¹,

Schmauder²

2009

IUTAM Symposium on Multi-Functional Material Structures and Systems

View full text Add to dashboard Cite

Fracture properties of interfacially doped Nb-Al2O3 bicrystals: II, relation of interfacial bonding, chemistry and local plasticity

Cited by 29 publications

References 80 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

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

Multiscale Simulation of Metal/Ceramic Interface Fracture

Contact Info

Product

Resources

About