Electrolytic processing of superalloy aerospace castings using choline chloride-based ionic liquids

Abbott, Andrew P.; D’Souza, N.; Withey, Paul; Ryder, Karl S.

doi:10.1179/174591912x13228247936644

Cited by 30 publications

(15 citation statements)

References 24 publications

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“…This methodology subsequently enables grain inspection and the identification of faulty castings prior to heat treatment and also prevents the formation of incipient melting during heat treatment [12]. Here we describe an extension of these studies and will focus on a discussion of the effect of electrolyte formulations and applied potential on the surface morphology of two superalloys CMSX-4 and CMSX-10 during electropolishing in DESs.…”

Section: Matec Web Of Conferencesmentioning

confidence: 99%

“…The γ phase occupies approximately 70% of the overall volume and elements in the superalloy such as Al, Ti, Ta are found in the highest concentrations in this region. Elements such as, Cr, Re, W, tend to aggregate towards and remain in the γ phase [6][7][8][9][10][11][12]. During withdrawal from the furnace and subsequent solidification, surface oxide scale is often formed on the casting as a result of the differential thermal contraction of the ceramic mould and the cooling metal.…”

Section: Introductionmentioning

confidence: 99%

“…Previously we have described a novel alternative to these types of electrolytes by using Deep Eutectic Solvents (DESs) to successfully remove the surface scale [12]. DESs are low toxicity ionic solvents based around complexing a quaternary ammonium salt (QAS) with a hydrogen bond donor (HBD) (alcohols/amines/carboxylic acids etc.)…”

Section: Introductionmentioning

confidence: 99%

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Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

D’Souza

Appleton

Ballantyne

et al. 2014

MATEC Web of Conferences

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Abstract.Here we describe the use of environmentally benign Deep Eutectic Solvents (DESs) to electropolish oxide casting scale from Ni based superalloy turbine blades. These new electrolytes are a viable alternative to hazardous and aggressive aqueous acids and etchants currently used to process these components. In addition we show that the DES electrolytes selectively expose the underlying surface structure of these superalloys. We demonstrate the ability of these electrolytes to preferentially etch either γ or γ phases depending on the choice of electrolyte formulation and the applied potential during the electrolytic etch on CMSX-4 R and CMSX-10 R alloys.

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Section: Matec Web Of Conferencesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

D’Souza

Appleton

Ballantyne

et al. 2014

MATEC Web of Conferences

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“…In this case we have shown that electrolytic methods utilising DES can be applied to remove oxide scale from SX castings as well as to remove residual surface stress prior to heat treatment. 25 In this study we have aimed to explore the utility of DES as electrolytes in the electropolishing of HIP consolidated test pieces produced using Rolls-Royce powder metallurgy Ni-based alloy RR1000.…”

Section: Introductionmentioning

confidence: 99%

Electropolishing and electrolytic etching of Ni-based HIP consolidated aerospace forms: a comparison between deep eutectic solvents and aqueous electrolytes

Goddard

Harris

Saleem

et al. 2017

Transactions of the IMF

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Here we report that the Deep Eutectic Solvent (DES), (Ethylene glycol) 2 (Choline chloride), (2Eg:ChCl)is an effective medium in electrolytic removal of the Fe rich layer from Ni based Hot Isostatic Press (HIP) consolidation and that it is capable of sustaining etching at higher rates and at higher current efficiencies than a comparable aqueous electrolyte formulated from methane sulphonic acid / glycolic acid (MSA/GA). At high etch rates the surface finish is not as good using 2Eg:ChCl but high etch rates, current efficiency and excellent surface finish can be obtained from a 90%/10% hybrid mixture of 2Eg:ChCl MSA/GA electrolytes. In this study we have set out to compare the electropolishing and bulk electrolytic etching of HIP formed bodies fabricated from RR1000 Ni based superalloys in aqueous methane sulphonic acid / glycolic acid (MSA/GA) electrolyte and in Deep Eutectic Solvent (DES) type ionic liquids. Samples consisting of HIP formed test coupons were electropolished under a range of conditions of current density and applied potential in either the DES (2Eg:ChCl) or MSA/GA electrolytes. The samples were then characterised using a combination of methods including scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical microscopy. Surface roughness and etch characteristics of the samples were determined after treatment in each of the electrolytes in order to establish the comparative efficacy of the DES. Here we present details of some of the challenges and methodologies as well as characterisation of model test pieces and forms using the scale-up facilities at the Ionic Liquids Demonstrator (ILD) facility at the University of Leicester.We show that the HIP alloy can be effectively removed under mild conditions using DES electrolytes that are of low toxicity, environmentally sustainable, relatively low cost and without the use of strong acids or chemical etchants.

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“…5% and 10% oxalic acid was added to improve the properties of the liquid formed. The components were mixed first and then stirred at 80°C, until a homogeneous mixture was obtained [25].…”

Section: Liquid Preparationmentioning

confidence: 99%

Electropolishing of Re-melted SLM Stainless Steel 316L Parts Using Deep Eutectic Solvents: 3 × 3 Full Factorial Design

Alrbaey

Wimpenny

Al-Barzinjy

et al. 2016

J. of Materi Eng and Perform

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SummaryThis three levels three factors full factorial study describes the effects of electropolishing using deep eutectic solvents on the surface roughness of re-melted 316L stainless steel samples produced by the Selective Laser Melting (SLM) powder bed fusion additive manufacturing method. An improvement in the surface finish of re-melted stainless steel 316L parts was achieved by optimizing the processing parameters for a relatively environmentally friendly ('green') electropolishing process using a Choline Chloride ionic electrolyte. The results show that further improvement of the response valueaverage surface roughness (Ra) can be obtained by electropolishing after re-melting to yield a 75% improvement compared to the as-built Ra. The best Ra value was less than 0.5μm, obtained with a potential of 4 volts, maintained for 30mins at 40C°.Electropolishing has been shown to be effective at removing the residual oxide film formed during the re-melting process. The material dissolution during the process is not homogenous and is directed preferentially towards the iron and nickel, leaving the surface rich in chromium with potentially enhanced properties. The re-melted and polished surface of the samples gave an approximately 20% improvement in fatigue life at low stresses (approximately 570MPa). The results of the study demonstrate that a combination of re-melting and electropolishing provides a flexible method for surface texture improvement which is capable of delivering a significant improvement in surface finish whilst holding the dimensional accuracy of parts within an acceptable range.2

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Electrolytic processing of superalloy aerospace castings using choline chloride-based ionic liquids

Cited by 30 publications

References 24 publications

Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

Electropolishing and electrolytic etching of Ni-based HIP consolidated aerospace forms: a comparison between deep eutectic solvents and aqueous electrolytes

Electropolishing of Re-melted SLM Stainless Steel 316L Parts Using Deep Eutectic Solvents: 3 × 3 Full Factorial Design

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Electrolytic processing of superalloy aerospace castings using choline chloride-based ionic liquids

Cited by 30 publications

References 24 publications

Removal of casting defects from CMSX-4®and CMSX-10®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

Removal of casting defects from CMSX-4®and CMSX-10®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

Electropolishing and electrolytic etching of Ni-based HIP consolidated aerospace forms: a comparison between deep eutectic solvents and aqueous electrolytes

Electropolishing of Re-melted SLM Stainless Steel 316L Parts Using Deep Eutectic Solvents: 3 × 3 Full Factorial Design

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Product

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Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent

Removal of casting defects from CMSX-4^®and CMSX-10^®alloys by electropolishing in a novel electrolyte; Deep Eutectic Solvent