Insights into the Plasticization Mechanism in Different 18Cr-8Ni Austenitic Stainless Steel: Study of the Phase Reverted Structure Versus Cold-Deformed Structure

作者：Wu, Lei; Hu, Chengyang^*; Ke, Rui; Misra, Raja Devesh Kumar; Zhong, Ming; Li, Guangqiang; Xu, Deming; Wan, Xiangliang^*; Wu, Kaiming

来源：Steel Research International, 2022, 93(11): 2200122.

DOI：10.1002/srin.202200122

• austenitic stainless steel
• mechanical properties
• microstructures
• plasticization mechanisms
• strengthening mechanisms

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 mu m) structure is developed by annealing the 90% CR structure at 850 degrees 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 (approximate to 10 area%; newly formed), DTs, and SIM (approximate to 44 vol%; newly formed) are observed in the 10% CR structure. The presence of numerous dislocation slips (approximate to 50 area%; newly formed) and a small amount of DTs and SIMs are observed in UFG/FG structure.

• 单位
  东北大学