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在含硼约15ppm 的 Fe-30wt-%Ni 合金中,硼在奥氏体晶界存在平衡与非平衡两类偏聚。等温偏聚动力学曲线上出现极大值,是晶界非平衡偏聚的重要特征。在较低温度下等温,非平衡偏聚促进了晶界硼相的析出和平衡偏聚的建立。在连续冷却的试样中,硼在晶界的偏聚是保温时形成的平衡偏聚和冷却时形成的非平衡偏聚的叠加。加热温度升高,其控制因素由前者转变为后者;冷却速度降低,后者增强。
In the Fe-30 wt-% Ni alloy containing about 15 ppm boron, there are two types of segregation of boron in the austenite grain boundary at equilibrium and non-equilibrium. Isothermal segregation kinetic curve appears on the maximum value, is an important feature of non-equilibrium segregation of grain boundaries. The isothermal and non-equilibrium segregation at lower temperature promoted the precipitation of B phase and the equilibrium segregation in the grain boundary. In continuously cooled specimens, the segregation of boron at the grain boundaries is a superposition of equilibrium segregation formed upon incubation and unbalanced segregation formed upon cooling. Heating temperature increases, the control factor from the former into the latter; cooling rate decreased, the latter enhanced.