Fracture of brittle particles in a ductile matrix

Wallin, Kim; Saario, Timo; Törrönen, Kari

doi:10.1007/bf00018353

Cited by 91 publications

(35 citation statements)

References 13 publications

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“…Other studies have also shown this size-dependence of the rate of damage accumulation (e.g. [2,12,25,26,31,38]), which is consistent with a statistic failure criterion commonly applied to ceramic materials [42].…”

Section: Particle Fracture-influence Of Particle Sizesupporting

confidence: 85%

“…Determination of the stress/strain partitioning has been attempted by a variety of methods, including the modified shear-lag model [39,42], the mean field approach [43][44][45], and finite element methods (FEM) [27, 28, 46-50, 27, 28, 46-50]. Only FEM can provide information on the evolution of local stress/strain distributions at (or near) the reinforcements, which are critical to the nucleation of damage.…”

Section: Introductionmentioning

confidence: 99%

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Influence of damage on the tensile behaviour of pure aluminium reinforced with ≥40 vol. pct alumina particles

et al. 2001

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Abstract-Particle reinforced composites are produced by infiltrating Al 2 O 3 particle beds with high purity Al (99.99%). These materials feature 40-60 vol. pct reinforcement homogeneously distributed in a pore-free matrix. Their tensile behaviour is studied as a function of reinforcement size and shape. Internal damage, in the form of particle fracture and matrix voiding, occurs from the onset of plastic straining. Its evolution with strain is monitored through changes in (i) stiffness and (ii) peak stress after incremental plastic straining and annealing. The influence of damage on the flow curves of the composites can be accounted for using basic postulates of continuum damage mechanics. Failure strains vary between 2 and 4%, and are a function of the rate of damage accumulation. An expression is derived to predict elongation to failure of damaging materials that fail by tensile instability, which gives good agreement with the experimental observations. 

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Section: Particle Fracture-influence Of Particle Sizesupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Influence of damage on the tensile behaviour of pure aluminium reinforced with ≥40 vol. pct alumina particles

et al. 2001

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“…This size dependence has been demonstrated experimentally and formed the first proposal for local probability as a function of both mechanical fields and initiator size [8]. A lack of size dependence in the approaches examined in [7] leads to significantly different predictions for the positions of critical initiators in a given stress field from those seen experimentally.…”

Section: Introductionmentioning

confidence: 91%

Cleavage Fracture Modelling for RPV Steels: Discrete Model for Collective Behaviour of Micro-Cracks

Abu-Muharib

Jivkov

James³

et al. 2013

Volume 6B: Materials and Fabrication

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The ability to predict variations in cleavage fracture toughness behaviour of ferritic RPV steels, accounting for the effects of irradiation and defect geometry, is vital to safety assessment and life extension decisions. Local approaches to cleavage fracture offer a promising methodology to accomplish such calculations. However, the limited progress achieved by improving the local failure probability expression suggests that the methodology for calculating global cleavage might not be adequately representing real material. The basis for the existing methodology is the weakest-link assumption that all individual failure events are independent and non-interacting. Here an approach is considered which utilises a microstructure-informed model incorporating the experimental knowledge needed to postulate deterministic criteria for particle rupture and micro-crack propagation, whilst accounting for the probabilistic distribution of particle sizes. This is then used in a lattice model that can help detail the evolution of the formation of micro-cracks on global failure, therefore inferring the suitability of the weakest-link assumption. Predicting the probability of cleavage fracture requires such models, as the macroscopic cleavage phenomenon is governed by a number of micro-structural features.The material microstructure is represented by a regular lattice of truncated octahedral cells forming a computational sitebond model, with sites located at the cell centres and connected by two distinct sets of bonds. These bonds are modelled with structural beam elements, which represent all the possible relative deformations between coordinated sites. Particles of various sizes are distributed in the bonds, based on an experimentally determined distribution of cleavage initiating particles in RPV steel (Euro Material A). Although only elastic deformations are considered here, the results demonstrate that the interactions between individual failure events could potentially have a strong effect on the way global failure is reached.Nucleation of micro-cracks by rupturing second-phase particles affects their subsequent formation. In particular, it was found that once formed there is a reduced probability of further development of micro-cracks at particles outside the crack planes and an enhanced probability of formation at particles along the crack planes. This will therefore influence the distribution of micro-crack sizes that could in principle be used to calculate the global probability of failure, and could lead to substantially different distributions of particle sizes, then used in the current local approach methods.

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“…11 This, I believe, has passed the test of time to become the accepted model for cleavage fracture in steel containing a distribution of spheroidal carbides. It has provided the basis for a number of 'local approach' statistical analyses of fracture toughness: one example being the 1984 paper by Wallin et al, 12 which cites the original RKR model 13 as well as the Curry-Knott work. Since this paper is post-1980 we know it has received the second largest number of citations of any MS paper (for unexplained reasons, papers before 1980 are not included in the Science Citation Index).…”

mentioning

confidence: 99%

“…Wallin subsequently developed the approach as the basis of the 'master curve' method embodied in ASTM E1921-05 and subsequent revisions. The rationale of the 1984 paper 12 was to address the 'size effect' (of crack front length). This was not explicitly treated in the Curry-Knott paper: it was acknowledged, but argued to be not relevant.…”

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confidence: 99%

Retrodigitisation and a personal perspective on fracture processes in engineering alloys

Knott¹

2010

Materials Science and Technology

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Last January, I wrote an editorial to mark the twenty-fifth year of publication of Materials Science and Technology. This year, I want to publicise two further ventures, related to the journal and its 'silver anniversary'. The first is the decision by Maney to digitise and make available online the full range of articles in MST, back to the first issue in 1985; and also the full content of MST's ancestor Metal Science Journal (MS). The second is the commissioning for MST of a select number of '25 year perspectives'. These will review advances in a particular topic over the preceding 25 years, but with an emphasis on the current state and on where that topic may develop in the future. The first two of these will be on 'Exchange coupled nanocomposite hard magnetic alloys', by Israel Betancourt and Hywel Davies, 1 and 'Miniaturised testing for engineering metals and ceramics' by Bryan Roebuck and colleagues (to appear in February). 2 The placing of MS online provides ready access to some 8000 pages of articles published between 1967 and 1984. In recognition of this, I have been asked to write something about the journal and, perhaps more controversially, draw up a selection of papers for 'highly recommended' re-reading. Such papers may have made a memorable impression when first encountered; they may have put forward new ideas that have stood the test of time; they may represent the 'state of the art' at the time written, and so hold historical interest. My list concentrates on papers dealing with fracture mechanisms in engineering alloys. The plan is to encourage my colleagues on the Editorial Board, and perhaps others, similarly to comment on papers in their own areas of special interest. My selection is highly personal: other selections are likely to be equally personal, and I apologise in advance to those who might feel aggrieved if they have not received mention. A limited amount of informed comment from the general readership could perhaps also be accommodated as a list of independent recommendations: rather like the comments written by last year's holiday-makers on a hotel's website. Many of the papers selected will be made generally accessible to readers for a initial period.

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Fracture of brittle particles in a ductile matrix

Cited by 91 publications

References 13 publications

Influence of damage on the tensile behaviour of pure aluminium reinforced with ≥40 vol. pct alumina particles

Influence of damage on the tensile behaviour of pure aluminium reinforced with ≥40 vol. pct alumina particles

Cleavage Fracture Modelling for RPV Steels: Discrete Model for Collective Behaviour of Micro-Cracks

Retrodigitisation and a personal perspective on fracture processes in engineering alloys

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