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Experimental investigation on the growth behavior of naturally- initiated small cracks in superalloy GH4169
Received date: 2014-02-27
Revised date: 2014-05-05
Online published: 2015-03-31
Supported by
National Level Project
The growth behavior of naturally-initiated small cracks in single edge notched tensile (SENT) specimens of nickel-based superalloy GH4169 is studied. Fatigue experiments are conducted under constant amplitude loading with the stress ratios R of 0.1 and 0.5 at room temperature. A significant small crack effect is evident in this alloy, and the major part of total fatigue life is consumed in small crack propagation phase. Fracture mode under cyclic loading is established by scanning electron microscopy (SEM) and energy dispersive spectra (EDS) analysis on specimen fracture surfaces. Small cracks initiate from material inclusions, namely Ti(C, N) or Nb(C, N). A transition of fracture mode from faceted, crystallographic fracture to classical striation type of fracture occurs, corresponding to the minimum growth rate at small crack growth rate curve before crack growth acceleration.
Key words： superalloy; small crack effect; fracture mode; inclusion; scatter
ZHANG Li , WU Xueren , HUANG Xinyue . Experimental investigation on the growth behavior of naturally- initiated small cracks in superalloy GH4169[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2015 , 36(3) : 840 -847 . DOI: 10.7527/S1000-6893.2014.0087
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