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研究了非平衡状态下Cu08wt% Cr 亚共晶合金的定向凝固过程。结果表明, 当温度梯度为30℃/cm , 生长速度分别为3μm /s 和30μm /s 时, Cu08w t% Cr 合金呈(α枝晶+ 共晶) 的非平衡凝固组织; 当温度梯度为30℃/cm 时, α枝晶一次间距随生长速度的增大而增大, 这与枝晶一次间距的Hunt模型在低速度段的规律一致, 而与KP模型的规律相反; Cr 纤维的形成主要与液态Cr 的表面张力、Cr 原子在液相中横向扩散能力及α枝晶间Cr 相的生长环境有关,增强Cr 原子的扩散能力,减小α枝晶侧向分枝及其间隙尺寸有助于规则Cr纤维的形成。
The directional solidification process of Cu08wt% Cr hypoeutectic alloy under non-equilibrium condition was studied. The results show that the Cu08wt% Cr alloy exhibits (αdendritic + eutectic) non-equilibrium solidification at a temperature gradient of 30 ℃ / cm and a growth rate of 3μm / s and 30μm / s, respectively When the temperature gradient is 30 ℃ / cm, the primary spacing of α dendrites increases with the growth rate, which is consistent with the regularity of Hunt model of dendrite spacing at low speed, but opposite to that of KP model . The formation of Cr fibers is mainly related to the surface tension of liquid Cr, the lateral diffusion of Cr atoms in the liquid phase and the growth environment of Cr phase between α dendrites, which enhances the diffusibility of Cr atoms and reduces the lateral branching of α dendrites And its gap size contribute to the formation of regular Cr fibers.