Evolution of grain boundary character distributions in alloy 825 tubes during high temperature annealing: Is grain boundary engineering achieved through recrystallization or grain growth?

Journal Article · Sun Jan 15 04:00:00 EST 2017 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.11.016· OSTI ID:22689690

Bai, Qin; Zhao, Qing ^[1]; Xia, Shuang ^[1]; Wang, Baoshun ^[2]; Zhou, Bangxin ^[1]; Su, Cheng ^[2]

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1. School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)
2. Technical Department, Jiuli Hi-Tech Metals Co., Ltd., Huzhou 313008 (China)

Grain boundary engineering (GBE) of nickel-based alloy 825 tubes was carried out with different cold drawing deformations by using a draw-bench on a factory production line and subsequent annealing at various temperatures. The microstructure evolution of alloy 825 during thermal-mechanical processing (TMP) was characterized by means of the electron backscatter diffraction (EBSD) technique to study the TMP effects on the grain boundary network and the evolution of grain boundary character distributions during high temperature annealing. The results showed that the proportion of ∑ 3{sup n} coincidence site lattice (CSL) boundaries of alloy 825 tubes could be increased to > 75% by the TMP of 5% cold drawing and subsequent annealing at 1050 °C for 10 min. The microstructures of the partially recrystallized samples and the fully recrystallized samples suggested that the proportion of low ∑ CSL grain boundaries depended on the annealing time. The frequency of low ∑ CSL grain boundaries increases rapidly with increasing annealing time associating with the formation of large-size highly-twinned grains-cluster microstructure during recrystallization. However, upon further increasing annealing time, the frequency of low ∑ CSL grain boundaries decreased markedly during grain growth. So it is concluded that grain boundary engineering is achieved through recrystallization rather than grain growth. - Highlights: •The grain boundary engineering (GBE) is applicable to 825 tubes. •GBE is achieved through recrystallization rather than grain growth. •The low ∑ CSL grain boundaries in 825 tubes can be increased to > 75%.

• OSTI ID: 22689690
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 123; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BACKSCATTERING
DEFORMATION
DISTRIBUTION
ELECTRON DIFFRACTION
GRAIN BOUNDARIES
GRAIN GROWTH
NICKEL BASE ALLOYS
RECRYSTALLIZATION
TEMPERATURE RANGE 0400-1000 K
TUBES