Hydrogen-induced Cracking in Pure Iron

The modulus and internal friction of Armco iron rere continuously measured during cathodic charging rith hydtogen to investigate crack initiation and grorth. The observed modulus decrease ras attributed to crack initiation and grorth. The internal friction increase doring cathodic charging ras atfributed to plastic deformation accompanying the crack formation. Both the modulos and internal friction behavior rere found to be a sum of tro parallel exponential processes. The tro exponential processes rare consistent rith difftrent sources of carbon for the crack-producing hydrogen bubble nucleation.