Internal convective effects on the lifetime of the metastable phase undercooled Fe–Cr–Ni alloys
Internal convective effects on the lifetime of the metastable phase undercooled Fe–Cr–Ni alloys
复制标题
内部对流对亚稳相过冷 Fe-Cr-Ni 合金寿命的影响
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
R. Hyers
中科院分区：
文献类型：
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作者：
Alaina B. Hanlon;D. Matson;R. Hyers
对Fe-12wt%Cr-16wt%Ni合金在电磁悬浮（EML）和静电悬浮（ESL）作用下的过冷样品进行了亚稳相寿命的对比研究。在EML中通过定位力和ESL中弱得多的Marangoni力在样品内诱导内部流动。正在测试的假设是，EML样品内的流动是足够强大的，以导致增长的亚稳枝晶偏转，使相邻枝晶的二次臂碰撞，导致早期成核的稳定相。使用商业计算流体动力学软件包进行模拟，以确定发生副臂碰撞所需的时间。数值计算的碰撞时间和亚稳相的实验寿命之间有定量的一致性。它已被确定，在EML样品中的诱导对流足够强，以引起碰撞，是最有可能的原因ESL和EML样品中的亚稳相的寿命之间的差异。
Differences have been observed between the lifetimes of the metastable phases of undercooled samples of Fe–12 wt% Cr–16 wt% Ni alloy which had been subjected to electromagnetic levitation (EML) and electrostatic levitation (ESL). Internal flow is induced within the samples by positioning forces in EML and much weaker Marangoni forces in ESL. The hypothesis being tested is that the flow within EML samples is strong enough to cause the growing metastable dendrites to deflect so that the secondary arms of adjacent dendrites collide, resulting in early nucleation of the stable phase. Simulations using a commercial computational fluid dynamics software package were performed to determine the time required for collision of the secondary arms to occur. There is quantitative agreement between the numerical time to collision and the experimental lifetime of the metastable phase. It has been determined that the induced convective flow in EML samples is strong enough to cause collision and is the most likely cause of the difference between the lifetimes of the metastable phases in ESL and EML samples.