Crack initiation and crack propagation under thermal cyclic loading

Bethge, K.; Münz, D.; Neumann, Jim

doi:10.1080/02619180.1990.11753464

Cited by 10 publications

(4 citation statements)

References 6 publications

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“…Thermal fatigue experiments with an austenitic steel (German designation 1.4948, grain dia 3&150 pm) were performed in the following manner [1,7]: circular plates, diameter d = 150 mm and thickness h = 20 mm, were repeatedly heated and cooled. Heating started from 270°C and 410°C was attained in about 4 min, cooling was performed by pressurized water flow on the plate surface for nearly 20 s. The thermal loading resulted in an equibiaxial stress state on the plate surface.…”

Section: Methodsmentioning

confidence: 99%

“…Interesting characteristics of isotropic fibre processes on the plane based on the intersection method are the number of intersections per unit length NL with a test line which is related to the specific length lA of the fibre process (i.e. the total length of all cracks per unit area) by (1) ?c l A = -i N ' and the so-called pair correlation function of the intersection points which describes the frequency of occurrence of point distances and some attractive or repulsive behaviour of the points of intersection and, hence, also the regularity of the crack pattern. So-called kernel estimation methods can be used for its estimation [6].…”

Section: Fibre Process Modelmentioning

confidence: 99%

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Statistical Characterization of Random Crack Patterns Caused by Thermal Fatigue

Winkler¹,

Brückner‐Foit

Riesch-Oppermann³

1992

Fatigue Fract Eng Mat Struct

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Thermal fatigue experiments performed with an austenitic steel give rise to an irregular pattern of cracks on the specimen surface. The investigations are aimed at characterizing the patterns in quantitative terms and at discerning trends with increasing numbers of cycles. Statistical methods based on different models of stochastic geometry are applied to take into account the random influence in pattern formation. Descriptive statistics as well as stochastic models are used to characterize the damage level. The stochastic models, such as fibre processes and random mosaics, will finally correlate the physical damage process with the random crack pattern observed. It is shown in this paper how the statistical characteristics of the random crack patterns can be related to the statistical characteristics of the stochastic models and the way the physical nature of the damage process influences these quantities.

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Section: Methodsmentioning

confidence: 99%

Section: Fibre Process Modelmentioning

confidence: 99%

Statistical Characterization of Random Crack Patterns Caused by Thermal Fatigue

Winkler¹,

Brückner‐Foit

Riesch-Oppermann³

1992

Fatigue Fract Eng Mat Struct

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“…The fatigue damage inf metallic materials can be subdivided into the stages of crack initiation, subcritical crack propagation, and final unstable fracture [14]. Crack initiation usually occurs at stress concentration sites originating from component geometry, machining irregularities or surface imperfections [15].…”

Section: Thermal Fatigue Failure In Die Casting Diesmentioning

confidence: 99%

Die Materials for Critical Applications and Increased Production Rates

Schwam¹,

Wallace²,

Birceanu³

2002

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A wide range of materials and coatings were provided as in-kind contributions to this project by manufacturers and suppliers. Bohler Uddeholm and Kind provided steels, BrushWellman provided copper-based alloys , CMW and Kulite provided tungsten-based alloys, CSM (an H.C. Stark company) provided molybdenum-based alloys, Allvac provided nickel-based alloys and Dynamet provided titanium based alloys. Coatings were provided by Badger Metals, Dynamic Metal Treating, IonBond, Balszers and Phygen. In addition, in-plant evaluation of some of these materials under production conditions was undertaken by Metaldyne (previously Lester Die Casting) and Saint Clair Die Casting. Valuable technical support and advise were received from DCD Technology on tooling issues. ABSTRACTDie materials for aluminum die-casting need to be resistant to heat checking, and have good resistance to washout and to soldering in a fast flow of molten aluminum. To resist heat checking, die materials should have a low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, good temper softening resistance, high creep strength, and adequate ductility. To resist the washout and soldering, die materials should have high hot hardness, good temper resistance, low solubility in molten aluminum and good oxidation resistance. It is difficult for one material to satisfy with all above requirements. In practice, H13 steel is the most popular material for aluminum die casting dies. While it is not an ideal choice, it is substantially less expensive to use than alternative materials. However, in very demanding applications, it is sometimes necessary to use alternative materials to ensure a reasonable die life. Copper-base, nickel-base alloys and superalloys, titanium-, molybdenum-, tungsten-base alloys, and to some extent yttrium and niobium alloys, have all been considered as potential materials for demanding die casting applications. Most of these alloys exhibit superior thermal fatigue resistance, but suffer from other shortcomings.The current project conducted a systematic evaluation of potential die materials and diffusion coatings available commercially. The first group of materials evaluated were advanced die steels developed in the late 90's and marketed since 2000. Two representatives of this group are the BohlerUddeholm Dievar and the Kind Co. TQ1. In

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“…The fatigue damage in metallic materials can be subdivided into the stages of crack initiation, subcritical crack propagation, and final unstable fracture [14]. Crack initiation usually occurs at stress concentration sites originating from component geometry, machining irregularities or surface imperfections [15].…”

Section: Thermal Fatigue Failure In Die Casting Diesmentioning

confidence: 99%

Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts

Schwam¹

2012

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Crack initiation and crack propagation under thermal cyclic loading

Cited by 10 publications

References 6 publications

Statistical Characterization of Random Crack Patterns Caused by Thermal Fatigue

Statistical Characterization of Random Crack Patterns Caused by Thermal Fatigue

Die Materials for Critical Applications and Increased Production Rates

Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts

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