Insights into the Plasticization Mechanism in Different 18Cr–8Ni Austenitic Stainless Steel: Study of the Phase Reverted Structure Versus Cold‐Deformed Structure. Issue 11 (15th August 2022)

• Record Type: Journal Article
• Authors: Wu, Lei; Hu, Chengyang; Ke, Rui; Misra, Raja Devesh Kumar; Zhong, Ming; Li, Guangqiang; Xu, Deming; Wan, Xiangliang; Wu, Kaiming
• Is Part Of: Steel research international. Volume 93:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-15
• Subjects: austenitic stainless steel -- mechanical properties -- microstructures -- plasticization mechanisms -- strengthening mechanisms; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.202200122
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : It is aimed to explain different tensile elongations in 18Cr–8Ni austenitic stainless steel (ASS) with various microstructures having the same yield strength by comparing the deformation mechanisms. The as‐received ASS is cold‐rolled (CR) at room temperature with thickness reductions of 10% and 90% (achieved following 14 passes). The ultra‐fine grain/fine grain (UFG/FG, average grain size (diameter): 0.5–2 μm) structure is developed by annealing the 90% CR structure at 850 °C over 300 s. The optical, scanning and transmission electron microscope, electron backscatter diffraction, and X‐ray diffraction techniques are applied to the microstructural features. The as‐received specimen contained equiaxed austenite and equiaxed dislocation cells, stacking faults, deformation twins (DTs), and strain‐induced martensite (SIM) coexist in the 10% CR and UFG/FG samples. Tensile tests are conducted, and the results reveal that 10% CR and UFG/FG structures exhibited similar yield strengths (550 MPa) under conditions of varying elongation properties, which is attributed to differences in the microstructure‐dependent deformation mechanisms. Dislocation slip (≈10 area%; newly formed), DTs, and SIM (≈44 vol%; newly formed) are observed in the 10% CR structure. The presence of numerous dislocation slips (≈50 area%; newly formed) and a small amount of DTs and SIMs are observed in UFG/FG structure. Abstract : The results illustrate that the extent of elongation in the ultra‐fine grain/fine grain (UFG/FG) structures is ≈30% more than that of the 10% cold‐rolled (CR) sample, which is attributed to the differences in deformation mechanisms. The mechanisms involve strain‐induced martensite (≈44 vol%; newly formed) in the 10% CR structure to dislocation slip (≈50 area%; newly formed) in UFG/FG structure.