Solid-liquid interface and growth rate range of Al2O3-based eutectic in situ composites grown by laser floating zone melting
Solid-liquid interface and growth rate range of Al2O3-based eutectic in situ composites grown by laser floating zone melting
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激光浮区熔化生长Al2O3基共晶原位复合材料的固液界面及生长速率范围
DOI：
10.1016/j.jallcom.2015.12.045
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Yang Wenchao
中科院分区：
文献类型：
--
作者：
Ren Qun;Su Haijun;Zhang Jun;Yao Bin;Ma Weidan;Liu Lin;Fu Hengzhi;Huang Taiwen;Guo Min;Yang Wenchao
采用激光浮区熔凝法制备了定向凝固Al_2O_3/Er_3Al_5O_(12)(EAG)共晶复合材料，研究了非平衡凝固条件下的固液界面特征和生长速率范围。采用快淬法获得了S-L固-液界面，分析了不同共晶成分下的组织形态和初生相。在稳定生长区，复合材料呈现典型的由Al_2O_3和EAG相互穿组成的“汉字”(CS)不规则共晶组织，而在淬火区，规则的共晶片层和CS组织共存。亚共晶成分中的初生Al_2O_3相存在于界面前沿和淬火区。与稳定生长区不同的是，在淬火区，随着凝固速度的增加，共晶片层间距没有明显减小。在此基础上，根据Jackson-Hunt(J-H)模型计算出淬火区的最大凝固速度小于1.26×10~3μm/S，过冷度为4.15K。
Directionally solidified Al2O3/Er3Al5O12(EAG) eutecticin situcomposites are prepared by laser floating zone melting (LFZM) to investigate the solid–liquid interface characteristic and growth rate range under non-equilibrium solidification conditions. The solid–liquid (S–L) interface isin situobtained by rapidly quenching, and its microstructure morphology and primary phase based on different eutectic compositions are analyzed. In stable growth zone, the composite presents typically “Chinese script” (CS) irregular eutectic structure consisting of interpenetrated Al2O3and EAG phases, but in quenched region the regular eutectic lamellae and CS structure are coexisted. Primary Al2O3phase in hypoeutectic composition is found both inS–Linterface front and quenched region. Different from the stable growth zone, in quenched region as the solidification rate increases, the eutectic lamellae spacing does not show obvious decrease. The minimum eutectic lamellae spacing is refined to about 200 nm when the solidification rate is increased up to 100 μm/s. On the basis, according to the Jackson-Hunt (J-H) model, the maximum solidification rate in quenched region is calculated to be smaller than 1.26 × 103μm/s, and the undercooling degree is 4.15 K.