Fatigue strength of tungsten-copper duplex structures for divertor plates

Seki, Masanori; Horie, Takeshi; Tone, Tatsuzo; Nagata, Kohsoku; Kitamura, K.; Shibutani, Yoji; Araki, T.

doi:10.1016/0022-3115(88)90277-2

Cited by 12 publications

(4 citation statements)

References 17 publications

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“…This has been attributed to the braze layer having superior mechanical properties to the parent copper material. Additionally Seki [14] has shown that cracks propagate in a tungsten to copper brazed joint in different directions during rotating bending tests at room temperature and at 200 • C. Any procedures developed to predict the life of such joints must be robust and capable of accounting for all failure case characteristics described above.…”

Section: Varying Failure Locationsmentioning

confidence: 97%

“…A fracture mechanics based approach has been developed by Seki [14] to estimate the fatigue crack propagation life of small defects in a brazed layer, however, this does not consider the scenario where cracks initiate in the parent materials where it is known to occur [2,15]. You [6] proposed using the approach detailed in ASME III [17] to predict life of either of the parent materials and Carter [18] detailed a method for predicting fatigue lives of brazed joints in heat exchangers.…”

Section: Previous Work On the Modelling And Fatigue Of Dissimilar Bramentioning

confidence: 99%

“…Compared to the fatigue of welded joints, relatively little work has been published on the fatigue of dissimilar brazed joints. Copper to silver and copper to tungsten brazed joints have been subjected to rotating bending and axial displacement control mechanical fatigue testing [12][13][14]. Copper to tungsten brazed joints have also been tested under thermal cyclic loading [15].…”

Section: Previous Work On the Modelling And Fatigue Of Dissimilar Bramentioning

confidence: 99%

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The challenges in predicting the fatigue life of dissimilar brazed joints and initial finite element results for a tungsten to EUROFER97 steel brazed joint

Hamilton¹,

Robbie²,

Wood³

et al. 2011

Fusion Engineering and Design

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This paper summarises the challenges in accurately predicting stress states in dissimilar brazed joints and presents initial results from a finite element analysis of a tungsten to EUROFER97 brazed joint. The residual stresses due to joint manufacture are presented and differences in stress distribution due to thermal and mechanical loading highlighted. The results from this analysis correlate well to experimental results from previous research however further validation is required. The challenges in developing fatigue assessment procedures for dissimilar brazed joints are also discussed. These fatigue assessment procedures are introduced and a validation strategy for such procedures is proposed

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Section: Varying Failure Locationsmentioning

confidence: 97%

Section: Previous Work On the Modelling And Fatigue Of Dissimilar Bramentioning

confidence: 99%

Section: Previous Work On the Modelling And Fatigue Of Dissimilar Bramentioning

confidence: 99%

See 1 more Smart Citation

The challenges in predicting the fatigue life of dissimilar brazed joints and initial finite element results for a tungsten to EUROFER97 steel brazed joint

Hamilton¹,

Robbie²,

Wood³

et al. 2011

Fusion Engineering and Design

View full text Add to dashboard Cite

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“…One of the reasons for cracking is liquid metal embrittlement (LME) of the steel in contact with molten copper under stressed conditions. The cracks in the brazed joints can also be created during their mechanical reliability tests (Ref [30][31][32][33]. Cracking at the interfacial layer under shear and high temperature were reported in these studies.…”

Section: Introductionmentioning

confidence: 83%

Cracking of Copper Brazed Steel Joints Due to Precipitation of MnS upon Cooling

Varanasi

Koncz-Horváth

Sycheva

et al. 2020

J. of Materi Eng and Perform

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The process of brazing of different steel grades by pure liquid copper foil was studied to reveal the critical conditions when cracks do or do not appear in the braze upon cooling without any external load. Steel grades C45 (S 0.030 wt.%, no Mn and no Cr), S103 (Mn 0.25 wt.% and S 0.020 wt.% with no Cr), CK60 (0.75 wt.% Mn, 0.07 wt.% S and 0.15 wt.% Cr) and EN 1.4034 (Cr 12 wt.%, Mn 1.0 wt.% and S 0.035 wt.%) are studied under identical conditions using copper foils of 70-microns-thick. The samples were held above the melting point of copper at 1100 °C under high vacuum for different time durations (between 180 and 3600 s) and then cooled spontaneously. The joints were found cracked during cooling after a certain critical holding time. This critical holding time for cracking was found to decrease with increasing the Mn content and the S content of steel. It is observed that cracking is due to the precipitation of a critical amount of MnS phase upon cooling. The MnS/Cu interface is the weakest interface in the joint (with adhesion ensured only by van-der-Waals bonds), which is broken/separated upon cooling due to difference in heat expansion coefficients of the sulfide and copper phases. Higher is the Mn and S content, shorter is the probable time required for crack to appear in the joint. The braze integrity diagram is constructed as function of solubility product of MnS in steel and holding time showing a stable crack-free technological region and an unstable technological region with high probability of crack formation.

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