Processing and compressive creep of cast replicated IN792 Ni-base superalloy foams

DeFouw, John D.; Dunand, David C.

doi:10.1016/j.msea.2012.07.099

Cited by 17 publications

(6 citation statements)

References 18 publications

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“…Nevertheless, similar structures (with pore sizes of the same order of magnitude) have been created from high melting point metals (.1300°C) by replication previously, 28,29 using alternative materials such as NaAlO 2 or SrF 2 for the preform, and would also be possible to make through other foam processing routes, such as those based on powder technologies. 30 …”

Section: Suitability Of Foams As Regeneratorsmentioning

confidence: 91%

Metal foam regenerators; heat transfer and storage in porous metals

et al. 2013

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Open pore metal foams may be of interest as regenerators because of their large specific surface area and their high porosity. In this experiment, three aluminum foam samples (pore size 2-2.36 mm and around 65% porosity) were manufactured by the replication process. The volumetric heat transfer coefficient and number of transfer units (NTU) of the foams and a packed bed of steel ball bearings (2 mm diameter) were determined using a single-blow transient technique over the range 500 , Re m , 1400. The NTU values of the foams and ball bearings both reduced with increasing Reynolds number (flow velocity). The pressure drop across the matrices increased with the velocity, though the values for the metal foams were much lower than that of the ball bearings, indicating that they may have potential for this type of application.

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Section: Suitability Of Foams As Regeneratorsmentioning

confidence: 91%

Metal foam regenerators; heat transfer and storage in porous metals

et al. 2013

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“…By having a melting point of 801 °C, it can be used with metals that have a melting point lower than this value, most commonly aluminum, but examples also exist of the use with materials such as bulk metallic glasses, by humidifying a mix of liquid palladium-based bulk metallic glass alloy and NaCl granules 15 . Substitution of the NaCl with higher melting point materials also permits the production of foams from higher melting point metals 16 . This may include other water-soluble materials, or insoluble ones including different types of sand.…”

Section: Introductionmentioning

confidence: 99%

“…Attach the top of the lid to the valve system with the gasket, clamp, bolt and butterfly nut. 16. Close all the valves of the system.…”

Section: Introductionmentioning

confidence: 99%

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Luna

Barari

Woolley

et al. 2014

JoVE

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Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many cases validated experimentally, for light weight or impact energy absorbing structures, as high surface area heat exchangers or electrodes, as implants to the body, and many more. Although great progress has been made in understanding their structure-properties relationships, the large number of different processing techniques, each producing material with different characteristics and structure, means that understanding of the individual effects of all aspects of structure is not complete. The replication process, where molten metal is infiltrated between grains of a removable preform material, allows a markedly high degree of control and has been used to good effect to elucidate some of these relationships. Nevertheless, the process has many steps that are dependent on individual "know-how", and this paper aims to provide a detailed description of all stages of one embodiment of this processing method, using materials and equipment that would be relatively easy to set up in a research environment. The goal of this protocol and its variants is to produce metal foams in an effective and simple way, giving the possibility to tailor the outcome of the samples by modifying certain steps within the process. By following this, open cell aluminum foams with pore sizes of 1-2.36 mm diameter and 61% to 77% porosity can be obtained.

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“…(20) and the stress exponent (n) is 0.34. It was reported that n should be > 3 under dislocation creep [28,29]. This indicates that the substrate would be subjected to the diffusional creep (Coble and Herring-Nabarro creep) rather than the dislocation creep.…”

Section: Determination Of the High Temperature Stressmentioning

confidence: 99%

“…This volume change leads to a significantly large stress. Since the β-(Pt, Ni)Al has a much lower resistant to plastic 29 deformation than the Pt-γ/γ' bond coat at high temperature (e.g., >750 °C). Therefore, under the high temperature stress, the β-(Pt, Ni)Al bond coat exhibits an intense roughening [18].…”

Section: Effect Of High Temperature Stress On the Surface Rumplingmentioning

confidence: 99%

High temperature stress and its influence on surface rumpling in NiCoCrAlY bond coat

et al. 2017

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The objective of this work is to develop a methodology to measure the high temperature stress in the bond coat, and investigate its role on the surface rumpling. We first presented an analytical model to evaluate the high temperature stress using X-ray sin 2 Ψ technique coupling with the curvature measurement at room temperature. A typical NiCoCrAlY bond coat with a Hastelloy-X substrate was employed as a model sample. During exposure at 1150 ºC , the bond coat was under tension at high temperature, increasing parabolically from 1.05 MPa after 12 h to 3.81 MPa after 120 h. To understand its effect on the surface rumpling, the bond coat surface roughness was recorded as a function of time, and compared with a bulk NiCoCrAlY alloy. A strong correlation between the bond coat stress and the surface roughness was identified. In addition, the origination of the bond coat stress and the rumpling mechanism were discussed. 2It was revealed that the high temperature stress in the bond coat was caused by the volume shrinkage from β-γ transformation, mainly due to the inter-diffusion. The grain sliding accompanied with diffusional creep in response to the bond coat stress controls the roughening.

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Processing and compressive creep of cast replicated IN792 Ni-base superalloy foams

Cited by 17 publications

References 18 publications

Metal foam regenerators; heat transfer and storage in porous metals

Metal foam regenerators; heat transfer and storage in porous metals

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

High temperature stress and its influence on surface rumpling in NiCoCrAlY bond coat

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