Iterative thermomechanical processing of alloy 600 for improved resistance to corrosion and stress corrosion cracking

By Abhishek Telang and Amrinder S. Gill and Mukul Kumar and Sebastien Teysseyre and Dong Qian and Seetha R. Mannava and Vijay K. Vasudevan
Published in Acta Materialia NULL 2016

Abstract

The effects of thermomechanical processing (TMP) with iterative cycles of 10% cold work and strain annealing, on corrosion and stress corrosion cracking (SCC) behavior of alloy 600 was studied. The associated microstructural and cracking mechanisms were elucidated using transmission (TEM) and scanning electron microscopy (SEM), coupled with precession electron diffraction (PED) and electron back scatter diffraction (EBSD) mapping. \TMP\ resulted in increased fraction of low coincident site lattice (CSL) grain boundaries whilst decreasing the connectivity of random high angle grain boundaries. This disrupted random grain boundary network and large fraction of low \CSL\ boundaries reduced the propensity to sensitization, i.e. carbide precipitation and Cr depletion. After TMP, alloy 600 (GBE) also showed higher intergranular corrosion resistance. Slow strain rate tests in 0.01

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