A comparative study of metastable phase separation for undercooled liquid Fe35Cu65 alloy under natural and forced cooling conditions
A comparative study of metastable phase separation for undercooled liquid Fe35Cu65 alloy under natural and forced cooling conditions
复制标题
DOI：
10.1016/j.jallcom.2022.167079
复制
发表时间：
2022-09
影响因子：
6.2
通讯作者：
Yuhao Wu;Baorong Zhu;Jingwen Su;Zhiming Gao;Xing Zhao
中科院分区：
文献类型：
--
作者：
Yuhao Wu;Baorong Zhu;Jingwen Su;Zhiming Gao;Xing Zhao
采用玻璃助熔技术和格子Boltzmann方法系统研究了冷却方式对过冷液态Fe 35 Cu 65合金亚稳相分离动力学的影响。在13-285 K的过冷度范围内观察到MPS。随着过冷度的增加，相分离时间线性增加。同时，显微偏析形态由靠近试样表面的富Fe球和远离试样表面的轮廓分明的αFe枝晶转变为由富Fe核浮动和富Cu壳下沉组成的偏心核壳宏观偏析形态。在强制冷却条件下，宏观偏析的形成需要较大的临界过冷度。与自然冷却试样相比，在相同过冷度下，强制冷却试样的相分离时间短得多，核壳宏观偏析偏心程度和富铁区体积分数也小得多。对液态Fe 35 Cu 65合金在自然冷却和强制冷却条件下的MPS和组织演变进行了数值模拟和实验验证。理论分析表明，富铁球的Stokes运动和Marangoni迁移所引起的流体动力学过程强烈依赖于MPS过程中富铁球的冷却方式、大小和位置。
The influences of the cooling style on metastable phase separation (MPS) kinetics of undercooled liquid Fe35Cu65alloy have been systematically investigated by glass fluxing technique and lattice-Boltzmann method. MPS was observed in the undercooling range of 13–285 K. With a rise in the undercooling, phase separation time increased linearly. Meanwhile, a microsegregation morphology, which appeared as Fe-rich globules near the sample surface and well-defined αFe dendrites far from the sample surface, transformed into the eccentric core-shell macrosegregation morphology composed of a floating Fe-rich core and a sinking Cu-rich shell. Under the forced cooling condition, the macrosegregation formation required a larger critical undercooling. In contrast with the naturally cooled sample, the phase separation time of forcedly cooled sample was much shorter, and both the eccentric level of the core-shell macrosegregation and the volume fraction of Fe-rich zone were smaller at the same undercooling. The MPS and microstructure evolution of liquid Fe35Cu65alloy under the natural and forced cooling conditions were numerically simulated and experimentally confirmed. Theoretical analyses revealed that the fluid dynamics caused by the Stokes motion and Marangoni migration of Fe-rich globules were strongly dependent on the cooling style, the size and the position of Fe-rich globules during the MPS.