Thermal aging effects on mechanical and electrochemical properties of stainless steel weld overlay cladding

An investigation on mechanical property and electrochemical behavior of the cladding materials aged at 400 °C for different times was carried out by small punch test (SPT) and double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The results showed that thermal aging contributed to spinodal decomposition and G-phase formation in the aged ferrite phase, as well as increase of nano-hardness of ferrite phase. The SP energy by the small punch tests decreased with increase of thermal aging time, which was related to the lattice distortions in G-phase and aged ferrite phase and their interactions with dislocations during deformation process. Thermal aging promoted corrosion and intergranular corrosion susceptibility of the cladding materials. Combined effects of G-phase and spinodal decomposition lowered intergranular corrosion resistance of the cladding material.