Premium
HUMID AIR EFFECTS ON CRACK TIP PLASTIC WORK IN 1008 STEEL
Author(s) -
Gross T. S.,
Joseph A. D.
Publication year - 1986
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.1460-2695.1986.tb01210.x
Subject(s) - materials science , fracture mechanics , paris' law , hydrogen , nitrogen , alloy steel , metallurgy , composite material , alloy , crack closure , fracture (geology) , work (physics) , chemistry , thermodynamics , physics , organic chemistry
The cyclic plastic work of fatigue crack propagation, Q pw , and the effective surface energy, U , were measured for an annealed 1008 steel in humid air and dry nitrogen using calorimetry Q pw was not significantly affected by the humid air environment suggesting that the hydrogen generated by the oxidation of iron at the crack tip does not strongly affect the cyclic properties for this material U was identical and constant for the two environments for crack growth rates greater than ∼ 100 A/cycle. Below d a /d N ∼ 100 A/cycle U decreased rapidly with decreasing δ K in the humid air environment It was concluded from these two observations that the main effect of hydrogen on crack growth in this alloy was to lower the atomic surface energy, γ, thereby lowering the local fracture stress.