THE INFLUENCE OF HYDROGEN ON DELAYED FAILURE IN TITANIUM ALLOYS

摘要

Notch geometry, strength level, hydrogen concentration and hydrogen distribution exerted an appreciable influence on delayed failure character¬istics of a 4 Al - 4 Mn, titanium alloy. Hydrogen-induced delayed failure in sharply notched material occurred bv a process of crack initiation and slow crack propagation. The average rate of crack growth was accelerated as the hydrogen content increased, and appeared to be independent of applied stress. The crack initiation and propagation process under certain condi¬tions of stress was complicated by room temperature creep. A high con¬centration of hydrogen at the surface of a specimen was conducive to early crack formation, and crack growth rates appeared dependent upon inward diffusion of hydrogen from the surface.