Effects of pre-creep on dislocation and tensile property of Cr-Ni steel. (6th January 2021)

• Record Type: Journal Article
• Authors: Pei, Hai-Xiang; Yang, Xiao-Min; Fang, Xu-Dong; Zhao, Yu-Hong; Huo, Hua
• Is Part Of: Materials research express. Volume 8:Number 1(2021)
• Publication Date: 2021-01-06
• Subjects: Cr-Ni steels -- dislocation -- Pre-creep; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/abd420
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: Pre-creep experiments were performed on chromium-nickel (Cr-Ni) stainless steel in the early stage of creep. The temperature was held for 500–2000 h under high-temperature load conditions (873 K and 150 MPa), and various analysis methods, including optical microscopy, electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and X-ray diffraction, were used to determine the pattern of dislocation evolution under different temperature-holding times. The results showed that the slip bands intersected at the initial stage of pre-creep, and a quadrilateral network structure was formed by the dislocation pinning. As the temperature-holding time increased, the dislocation network began to climb to form dislocation walls, dislocation cells, and other substructures. At 2000 h, the grain boundaries widened considerably; creep holes were found at the grain boundaries; and dislocation pairs with oscillating contrast occurred, which indicates nitrogen diffusion. The yield and tensile strengths of the Cr-Ni steel samples subjected to pre-creep at holding times of above 1000 h decreased after they were subjected to room-temperature tensile tests.