Influence of grain boundary character distribution and random high angle grain boundaries networks on intergranular corrosion in high purity copper

Recently, as vital factors for corrosion resistance, grain boundary character distribution and random high angle grain boundaries networks gradually gained extensive attention. And grain boundary engineering was widely used in improving intergranular corrosion resistance of face-centered-cubic materials, such as austenitic stainless steel, nickel-based alloy and lead alloy, etc. But the relevant research on high-pure copper was rarely studied. In this work, the intergranular corrosion behavior of high purity copper was investigated by potentiodynamic polarization tests in 0.1 M sodium chloride. And the influence of grain boundary character distribution (GBCD) and random high angle grain boundaries network (RHGBN) connectivity were explored. The contribution of multiple-twinning process to interrupt RHGBN connectivity was analyzed. Results clearly demonstrated that GBE samples all exhibited a high resistance to intergranular corrosion (IGC), particularly, sample with higher fraction of low-Sigma CSL boundaries (GBE-1) or with lower RHGBN connectivity (GBE-3) both had a higher resistance to IGC. Multiple-twinning process during annealing was the key factor to interrupt the connectivity of random high angle boundaries network. (C) 2019 Published by Elsevier B.V.