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Mechanical testing of high-temperature materials: modelling data-scatter

  • B. F. Dyson

Abstract

Scatter in mechanical property data of a metallic alloy derives from two sources: a variable microstructure or an inadequate and sometimes badly executed test method. A quantified example of each source of scatter is given in this paper by examining two important high-temperature properties: uniaxial tensile creep and low-cycle fatigue. Creep-lifetime data of engineering alloys often show scatter-bands much greater than can be accounted for on the basis of well-understood physics of testing-induced scatter. Bounds to this material-induced scatter have been computed for a low-alloy ferritic steel dataset using a physically based creep model incorporating damage state variables. High-temperature low-cycle fatigue demands a more complicated test procedure than does steady-load creep and the large interlaboratory scatter found in recent round robin data from 26 laboratories in Europe and Japan has highlighted inadequacies in the standardized test method. A simple material model and fracture criterion has been used, in conjunction with a previously introduced testpiece-bending model, to predict testing-induced interlaboratory scatter for the two nickel-base superalloys reported upon in the round robin exercise.

Keywords

Strain Range Tertiary Creep Testing Practice Total Strain Range Uniaxial Creep 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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© Springer Science+Business Media Dordrecht 1996

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  • B. F. Dyson

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