Measurement of crack growth rate of alloy X-750 based on DCPD method

This paper studies the fatigue cracking in air and stress corrosion cracking (SCC) in high temperature and high pressure water of alloy X-750 respectively based on direct current potential drop (DCPD) method. The testing method using compact tensile specimens is briefly described, and the mechanism and process that control the crack tip chemistry are discussed according to the slip-film rupture-oxidation model. The effects of dissolved oxygen and SO{sub 4}{sup 2-} impurities on crack tip chemistry are also discussed. (authors)