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ELEVATED TEMPERATURE FATIGUE IN Ni 3 Al‐BASED ALLOYS
Author(s) -
GORDON D. E.,
Unni C. K.,
STOLOFF N. S.
Publication year - 1994
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1994.tb00831.x
Subject(s) - materials science , low cycle fatigue , superalloy , alloy , fatigue limit , metallurgy , precipitation hardening , hardening (computing) , fatigue testing , composite material , layer (electronics)
— Both high‐cycle and low‐cycle fatigue properties of hot‐extruded powders of a Ni 3 Al‐based alloy, IC218, have been evaluated. High cycle fatigue measurements were performed under stress controlled conditions at temperatures ranging from 25°C to 850°C. Tests were made in both laboratory air and vacuum environments. Low cycle fatigue tests were conducted under total strain control in a laboratory air environment at 650°C. In high cycle fatigue, high ratios of the fatigue limit (Δσ at 10 6 cycles) to monotonic yield strength (σ ys ), of approximately Δσ/σ ys ∼1, were obtained in the powder extruded IC218 alloy for temperatures ranging from 25°C to 650°C. In low cycle fatigue, a substantial decrease in fatigue life occurred at 650°C, compared to results obtained previously at 25°C. High cycle fatigue performance at low stress/strain amplitudes is better than expected when compared to precipitation strengthened superalloys. The improved performance is explained in terms of the cyclic hardening behavior of the alloy.