EFFECT OF HYDROGEN ON THE CRITICAL STRESS INTENSITY FACTOR FOR DISLOCATION EMISSION FROM A CRACK TIP AND DFZ
氢对裂尖释放位错临界应力强度因子K_e和无位错区DFZ的影响

Theoretical calculation indicates solute hydrogen makes the criti-cal stress intensity factor for dislocation emission from a crack tip decreaseddue to the reduction of the friction stress of lattice by hydrogen;Emittedfrom a crack tip,disilocation carries a fraction of hydrogen atoms gatheringthere and is exerted by an additional attractive force,which makes the DFZshort.TEM in-situ tensile experimental results show(1) the critical stressintensity factor for dislocation cmission was decreased when pure iron was ten-sioned in H_2 gas in environmental cell(2)no DFZ was observed for Fe-3%Si single crystal after hydrogen charging(3)a DFZ was present for polycrys-talline Fe-3% Si alloy with hydrogen charging after predeformation.All resul-ts demonstrate the theoretical model.