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THE EFFECT OF HYDROGEN ON FATIGUE AND DISLOCATION BEHAVIOR OF AN α/β TITANIUM ALLOY
Author(s) -
MOODY N. R.,
GERBERICH W. W.
Publication year - 1982
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.1460-2695.1982.tb01224.x
Subject(s) - hydrogen , materials science , slip (aerodynamics) , grain size , alloy , metallurgy , titanium alloy , grain boundary , lüders band , dislocation , composite material , microstructure , thermodynamics , chemistry , physics , organic chemistry
— Fatigue thresholds and crack growth rates were studied in the experimental alloy, Ti—5Al—4Mo, as a function of temperature, grain size and hydrogen concentration. Deformation is confined to planar slip bands along which fracture occurred at low hydrogen concentrations. Hydrogen accelerated crack growth rates at various combinations of temperature, grain size and hydrogen with a corresponding change in fracture from “cleavage’ to interface phase fracture. In addition, hydrogen was found to promote interface phase formation. It is proposed that stress‐assisted hydrogen accumulation increases the interface phase hydrogen concentration which reduces the interface phase fracture stress. This process depends on the local stress and β ‐phase hydrogen concentrations, temperature and the time under load. At 340 K, hydrogen had a relatively small effect on crack growth due to a change in slip behavior with increased hydrogen concentration.