Improving Intergranular Stress Corrosion Cracking Resistance in a Fe–18Cr–17Mn–2Mo–0.85N Austenitic Stainless Steel Through Grain Boundary Character Distribution Optimization

Abstract

The grain boundary character distribution (GBCD) optimization and its effect on the intergranular stress corrosion cracking (IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18Cr-17Mn-2Mo-0.85N high-nitrogen nickel-free austenitic stainless steel were systematically explored. The results show that stacking faults and planar slip bands appearing at the right amount of deformation (lower than 10%) are beneficial cold-rolled microstructures to the GBCD optimization. The proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth, accompanying with the growth of twin-related domain in the experimental steel. In this way, the fraction of low Σ coincidence site lattice (CSL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 h. After GBCD optimization, low Σ CSL boundaries and the special triple junctions (J2, J3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest, thus improving the IGSCC resistance of the experimental steel.

Evolution of Grain Boundary Character Distribution in B10 Alloy from Friction Stir Processing to Annealing Treatment

“…The TRD map of the BM specimen is displayed in Figure 2 d. Detailed quantitative data reveals that the BM specimen exhibited a limited development of multiple twinning, as evidenced by the average number of grains per TRD and LLC of 2.26 and 1.07, respectively. The RBs prefer the formation and propagation of intergranular cracks compared to low-Σ CSL boundaries [ 33 , 34 ]. It suggests that the BM specimen was susceptible to intergranular failure.…”

A Review on Controlling Grain Boundary Character Distribution during Twinning-Related Grain Boundary Engineering of Face-Centered Cubic Materials

“…The results indicated an increase in crack arrest probability, suggesting improved resistance to corrosion and SCC after TMP treatment. Shi et al [ 135 ] optimized GBCD to enhance the IGSCC resistance of Fe-18Cr-17Mn-2Mo-0.85N high-nitrogen nickel-free austenitic stainless steel. It was suggested that high proportions of low-ΣCSL boundaries and special triple junctions (2-CSL and 3-CSL types) contribute to enhancing the IGSCC resistance of high-nitrogen steel by hindering the precipitation of intergranular nitrides along grain boundaries and preventing the intergranular propagation of cracks.…”