The relationship between electric processing condition and microstructure in the solidification of multicomponent oxides
The relationship between electric processing condition and microstructure in the solidification of multicomponent oxides
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DOI：
10.1016/j.ceramint.2023.03.133
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发表时间：
2023-05-02
影响因子：
5.2
通讯作者：
Qin，Rongshan
中科院分区：
文献类型：
--
作者：
Bhagurkar，Ashutosh;Qin，Rongshan
本文系统地研究了电脉冲处理条件与显微组织之间的关系。研究发现，电脉冲可以显着细化孔隙率并改变晶粒形态。采用最佳电脉冲工艺参数处理后的试样，其孔隙体积分数和平均孔径分别比未经电脉冲处理的试样降低了75%和70%以上。电流处理促进了一次枝晶臂厚度较小的枝晶生长，阻止了液相在生长的固相晶粒间的滞留。前者是由电增强的动力学迁移率对枝晶尖端曲率半径的影响引起的。后者归因于电热力学对微结构形成的影响，如导电相的连接性增强。电脉冲处理获得的组织有利于热传导、组织强度和裂纹抑制。然而，过多的脉冲频率和脉冲宽度会产生不需要的热量来抵消电效应。研究揭示了氧化物材料与金属和合金在完全不同的凝固条件下电加工条件与显微组织的关系。结果从相反的方面证实了脉冲凝固的有效性。
Systematic characterization for the relationship between the electropulse processing conditions and microstructure has been carried out in the present work. It is found that electropulse can refine porosity and alter grain morphology considerably. A processing with optimum electropulsing parameters can reduce over 75% volume fraction of porosity and more than 70% average pore diameter in comparison with that of reference sample without electric treatment. Electric current treatment promotes the growth of dendrites with smaller thickness of primary arms dendrite and prevents the liquid entrapping between the growing solid grains. The former is caused by the effect of electricity-enhanced kinetic mobility on the radius of curvature at the tip of dendrite. The latter is attributed to the effects of electric thermodynamics on the microstructural formation such as the enhanced connectivity of conductive phase. The microstructures obtained by electropulsing treatment are favourable for heat conduction, structural strength and crack prohibition. However, the excess pulse frequency and pulse width can generate unwanted heat to counteract electric effect. The research reveals the relationship between electric processing conditions and microstructure in a perfectly controversial solidification condition in oxide materials to that of the metals and alloys. The results confirm from the opposite side the validity of the pulsated solidification.