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在含硼20×10-6的GH128合金TLP扩散连接区中,硼在奥氏体晶界存在两类偏聚,即平衡偏聚和非平衡偏聚.晶界非平衡偏聚的一个重要特征是等温偏聚动力学曲线上出现极大值.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.在连续冷却时,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迭加.加热温度升高,其控制因素由前者转变成后者;冷却速度降低,后者增强.
There are two types of segregation at the austenite grain boundary in the TL12 diffusion bonded region of GH128 alloy containing 20 × 10-6 boron, ie, equilibrium segregation and non-equilibrium segregation. An important feature of the unbalanced segregation at the grain boundary Is the maximum value of isothermal segregation kinetic curve.It isothermal and non-equilibrium segregation promotes the precipitation of B phase and equilibrium segregation at lower temperature.When continuous cooling is carried out, Poly is formed when the insulation balance of segregation and cooling formed when the non-equilibrium segregation superimposed heating temperature increases, the control factor from the former into the latter; cooling rate decreased, the latter enhanced.