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# Heat treatment of nickel based superalloys for turbine blade application: modelling and validation

Cosentino, Francesco (2013)
Ph.D. thesis, University of Birmingham.

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## Abstract

A numerical model has been developed for the simulation of the vacuum heat treatment and high pressure gas quenching used during the manufacture of single crystal turbine blades, of the type used for aeroengine applications. Heat transfer by radiation and forced convection is taken into account to obtain quantitative predictions of the thermal history of the components during ramping-up, holding and gas fan quenching. The uniformity of the temperature is investigated and the effectiveness of the treatment is assessed. Simulations of the quenching process have allowed visualisation of the flow field and prediction of the local quench rate as a function of the furnace parameters. The results of the modelling have been validated against thermocouple measurements made on laboratory-scale vacuum furnace with many of the characteristics of the type used in industrial production. The modelling methodology is extended to industrial scale processes via a multi-scale decomposition approach. The effect of quench rate on the microstructure of CMSX-10 has been characterised using scanning electron microscopy. It is shown that the precipitate size distribution correlates directly with the local quenching rate. To understand the influence of the microstructure on creep performance, two structures with different average $$\gamma$$’ size have been tested in creep over a wide range of temperatures and applied stress levels. Particularly in the low temperature / high stress regime, the size of the precipitates markedly determines the creep performance observed.

Type of Work: Ph.D. thesis. Reed, Roger C. (Roger Charles) Colleges (2008 onwards) > College of Engineering & Physical Sciences School of Metallurgy and Materials Full thesis embargoed until 31/01/2021. Parts of this thesis have appeared in the following publications and conferences: F. Cosentino, N.Warnken, J.-C. Gebelin, and R. C. Reed, "Numerical modelling of vacuum heat treatment of nickel-based superalloys". Submitted for publication to Metallurgical and Materials Transactions A, 2012. F. Cosentino, N. Warnken, J.-C. Gebelin, and R. C. Reed, "Modelling of gas fan quenching for heat treatment of nickel-based single crystal superalloys" Submitted for publication to the Journal of Materials Processing Technology F. Cosentino, N.Warnken, J.-C Gebelin and R. C. Reed "Modelling of heat treatment of nickel based superalloys" at EUROMAT 2011, Montpellier, France, 12 - 15th September, 2011. F. Cosentino, N. Warnken, J.-C Gebelin, R. W. Broomfield and R. C. Reed "Computational fluid dynamics modelling of heat treatment of single crystal nickel based superalloys for turbine blade application" at Superalloys 2012: The 12th International Symposium on Superalloys, September 9 to 13, 2012, Seven Springs Mountain Resort, Champion, Pennsylvania, USA. F. Cosentino, J.-C Gebelin, N. Warnken and R. C. Reed "Multi Scale modelling of high pressure gas fan quenching" at 9th International Conference on CFD in the Mineral and Process Industries, Melbourne, Australia, 10-12th December 2012. TJ Mechanical engineering and machineryTN Mining engineering. Metallurgy University of Birmingham 4250
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.

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