| Title |
On the Crystallographic Features of Cr2N Precipitates in High-Nitrogen Austenitic Stainless Steel (1) -1. Precipitation Behavior of the Second Phases during Isothermal Aging at 900℃ |
| Authors |
이태호(Tae Ho Lee); 오창석(Chang Seok Oh); 이창길(Chang Gil Lee); 김성준(Sung Joon Kim); 고목절웅(Setsuo Takaki) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
High nitrogen steel; HNS; Precipitation; Cr2N; σ-phase and Thermodynamic calculation |
| Abstract |
In these sequential papers, the crystallographic features of Cr₂N precipitates in high-nitrogen austenitic stainless steel (HNS) were investigated with particular emphasis on the crystal structure of Cr₂N. In the first part of this study, the precipitation behavior of the second phases were examined utilizing electron microscopy and thermodynamic calculation. The precipitation sequence of the Cr₂N was found to be intergranular, cellular, and intragranular precipitation with aging time. Based on the analyses of SAD patterns, the orientation relationship between y and Cr₂N was found to be [011], [1100]_(Cr₂N) and (111)γ (0001)_(Cr₂N). On prolonged aging, the coarse a-phase with bet structure precipitated along grain and cell boundaries. The precipitation of a-phase could be explained by the mechanism that formation of nitrogen-depleted zone near Cr₂N induced nucleation of the a-phase, which was supported by thermodynamic calculation and electron microscopy. (Received August 23, 2004) |