Being able to predict creep strain as a function of time is important both in preventing aeroengine blades from rubbing against their outer casings, but also in being able to convert small punch test data into equivalent uniaxial test results using numerical models. The capability of the Wilshire equation to interpolate creep curves was assessed using uniaxial creep tests carried out on RR1000. In this paper, an artificial neural network was used to modify the Wilshire equation for times taken to reach various strains, so that the parameters of the Wilshire equation could be interpolated as a function of strain. The model was then evaluated using statistics on predictive accuracy, which showed that the model was capable of predicting the shape and scale of the creep curves with high accuracy. These modifications also revealed that the activation energy is dependent upon the average internal stress and thus strain.
AbdallahZPerkinsKWilliamsS.Advances in the Wilshire extrapolation technique-full creep curve representation for the aerospace alloy Titanium 834. Mater Sci Eng A. 2012; 550:176–182. http://dx.doi.org/10.1016/j.msea.2012.04.054.
2.
Strategic Research Agenda. Materials UK Energy Review: Report 1, Energy Materials; 2007.
3.
WilshireBBattenboughAJ.Creep and creep fracture of polycrystalline copper. Mater Sci Eng A. 2007; 443:156–166.
4.
WhittakerMTHarrisonWJ.Evolution of Wilshire equations for creep life prediction. Mater High Temp. 2014; 31:233–238.
5.
WilshireBScharningPJ.Prediction of long term creep data for forged 1Cr-1Mo-0.25V steel. Mater Sci Technol. 2008; 24(1):1–9.
6.
WilshireBWhittakerM.Long term creep life prediction for grade 22 (2·25Cr-1Mo) steels. Mater Sci Technol. 2011; 27(3):642–647.
7.
EvansM.Incorporating specific batch characteristics such as chemistry, heat treatment, hardness and grain size into the Wilshire equations for safe life prediction in high temperature applications: An application to 12Cr stainless steel bars for turbine blades. Appl Math Model. 2016; 40(23–24):10342–10359.
8.
WilshireBScharningPJ.A new methodology for analysis of creep and creep fracture data for 9–12% chromium steels. Int Mater Rev. 2008; 53(2):91–104.
9.
WhittakerMTEvansMWilshireB.Long-term creep data prediction for type 316H stainless steel. Mater Sci Eng A. 2012; 552:145–150.
10.
WilshireBScharningPJ.Extrapolation of creep life data for 1Cr-0.5Mo steel. Int J Press Vessel Pip. 2008; 85:739–743.
11.
WhittakerMTHarrisonWJLancasterRJAn analysis of modern creep lifting methodologies in the Titanium alloy Ti6-4. Mater Sci Eng A. 2013; 577:114–119.
12.
WhittakerMTHarrisonWJWilliamsS.Recent Advances in Creep Modelling of the Nickel base superalloy. Alloy 720Li Mater. 2013; 6:1118–1137.
13.
EvansMWilliamsTA.Assessing the capability of the Wilshire equations in predicting uniaxial creep curves: an application to Waspaloy. Int J Press Vessel Pip. 2019; 172:153–165.
14.
MitchellRJLemskyJARamanathanRProcess development and microstructure and mechanical property evaluation of a dual microstructure heat treated advanced Nickel disc alloy. In: ReedRC, editor. Superalloys. Warrendale: Tms-Minerals; 2008. p. 347–356.
15.
MitchellRJHardyMCPreussMDevelopment of γ′ morphology in P/M rotor disc alloys during heat treatment. In Proc Int Symp Superalloys. 2004:361–370.
16.
ReedRC.The superalloys: fundamentals and applications. Cambridge: Cambridge University Press; 2006.
17.
ChongYLiuZGodfreyAThe application of grain boundary engineering to a nickel base superalloy for 973 K (700°C) USC power plants. Metall Mater Trans E2014; 1(1):58–66.
18.
MonkmanFCGrantNJ.An empirical relationship between rupture life and minimum creep rate in creep-rupture tests. Proc ASTM. 1956; 56:593–620.
19.
AbdallahaZPerkinsKWilliamsS.Advances in the Wilshire extrapolation technique–full creep curve representation for the aerospace alloy Titanium 834. Mater Sci Eng A. 2012; 550(30):176–182.
20.
HarrisonWWhittakerMTWilliamsS.recent advances in creep modelling of the nickel base superalloy. Alloy 720Li. Mater. 2013; 6:1118–1137.
21.
GrayVWhittakerMT.Development and assessment of a new empirical model for predicting full creep curves. Materials (Basel). 2015; 8:4582–4592.
22.
MartinVCHurnSHarrisD.Econometric Modelling with time series: specification, estimation and testing. Cambridge: Cambridge University Press; 2013.
23.
DaviesRG.On the activation energy of high temperature creep. Acta Metall. 1961; 9:1035–1036.
24.
EstrinYMeckingH.A unified phenomenological description of work hardening and creep based on one-parameter models. Acta Metall. 1984; 32(1):57–70.
25.
AkaikeH.On entropy maximisation principle. In: KrishniahPR, editor. Applications of statistics. Amsterdam: North-Holland; 1977. p. 27–41.
26.
DunandDCHanBQJansenAM.Monkman-Grant analysis of creep fracture in dispersion-strengthened and particulate-reinforced aluminium. Metall Mater Trans A. 1999; 30(13):829–838.
27.
HoldenKPeelDAThompsonJL.Economic forecasting: an introduction. Cambridge: Cambridge University Press; 1990.
