Environment assisted cracking of target structural materials under different loading conditions

Venkataramakrishnan Selvaraj, University of Nevada, Las Vegas


Martensitic Alloy HT-9 has been tested for its evaluation of stress corrosion cracking resistance in neutral and acidic solutions at ambient and elevated temperatures incorporating smooth and notched cylindrical specimens under constant load and slow strain rate (SSR) conditions. C-ring and U-bend specimens have also been tested for stress corrosion cracking evaluation in the acidic solution. The role of hydrogen on the cracking tendency has been evaluated by cathodic applied potential; The results of constant load testing enabled the determination of the threshold stress for stress corrosion cracking in susceptible environments. The magnitudes of ductility parameters were reduced with increasing temperature. C-ring specimens showed cracKing Secondary cracks were observed by optical microscopy in specimens tested by the SSR technique. Fractographic evaluations by scanning electron microscopy revealed dimpled microstructure indicating ductile failure, and intergranular/transgranular brittle failures along the primary fracture face of the tested specimens.