Crystallization of undercooled liquid spinodals: Part II
Crystallization of undercooled liquid spinodals: Part II
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DOI：
10.1557/jmr.1999.0494
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发表时间：
1999-09
影响因子：
2.7
通讯作者：
K. L. Lee;H. Kui
中科院分区：
文献类型：
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作者：
K. L. Lee;H. Kui
我们在“过冷熔融Pd_80Si_20的相分离：第一部分”中证明，当熔融Pd_80Si_20钢锭在Δ T≥220 K （Δ T = t_1 - T，其中t_1为液相线，T为过冷熔体的温度）的情况下过冷至过冷状态时，通过spinodal分解发生液相相分离。在结晶过程中，一种亚稳液体spinodals变为Pd_3Si，另一种变为Pd_9Si_2。在这两种情况下，钯粒子都析出。微观结构分析表明，Pd_3Si子网首先形成。然后，它作为剩余过冷熔体后续结晶的种子，最终形成Pd_9Si_2枝晶。结晶过程中，潜热和体积收缩引起结晶形态的变化。
We demonstrated in “Phase separation in undercooled molten Pd_80Si_20: Part I” that when a molten Pd_80Si_20 ingot is undercooled into its undercooling regimen with Δ T ≥ 220 K (Δ T = T _1 – T , where T _1 is the liquidus and T is the temperature of the undercooled melt), liquid-state phase separation by spinodal decomposition occurs. On crystallization, one of the metastable liquid spinodals becomes Pd_3Si, whereas the other one turns into Pd_9Si_2. In both cases, Pd particles precipitate out. Microstructural analysis indicates the Pd_3Si subnetwork forms first. It then acts as a seed for the subsequent crystallization of the remaining undercooled melt, which finally forms the Pd_9Si_2 dendrites. As crystallization proceeds, latent heat and volume contraction bring about morphological changes.