Effects of 3-D grain boundary geometrical angles and the net normal stress on intergranular stress corrosion cracking initiation in a 316 stainless steel

Abstract

The dependence of intergranular stress corrosion cracking (IGSCC) initiation propensity on the grain boundary (GB) characters and geometrical angles was investigated by utilizing a thin sheet 316 stainless steel sample, of which the thickness was approximately equal to the average grain diameter. The low-ΣCSL GBs especially the Σ3 GBs had higher resistance to cracking initiation. The cracking initiation susceptibility (CIS) of a GB increased with the decrease in the GB inclination angle α. The net effective normal stress (Δ*σN) exerted on a GB increased with the Schmid factor mismatch (Δm) between the two-side grains. It was found that the Δ*σN initially slightly increased with Δm when 0≤Δm≤0.04, and then steeply increased with Δm when 0.04<Δm≤0.18. A criterion was proposed to predict the CIS of a GB, which demonstrated that the CIS of a GB with the Δ*σN over 0.06 would be high.