Interfacial morphology evolution in directionally solidified Al-1.5%Cu alloy  

Al-1.5%Cu合金定向凝固界面形态演化（英文）

作　　者：屈敏[1,2] 刘林[2] 崔岩[1] 刘峰斌[1] 

机构地区：[1]北方工业大学机械与材料工程学院,北京100144 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第2期405-411,共7页中国有色金属学报（英文版）

基　　金：Project(SKLSP201418)supported by the Fund of the State Key Laboratory of Solidification Processing in North China University of Technology,China;Projects(51171151,51331005)supported by the National Natural Science Foundation of China

摘　　要：The solid-liquid interracial morphology evolution was investigated in directional solidification （DS） of Al-1.5%Cu alloy （mass fraction）. The results show that the solidified microstructural evolution is gradual other than sharp, and the microstructure patterns are interesting and diversiform at the pulling rate ranging from 30 μm/s to 1500 μm/s. Indeed, dendrite to cell transition follows this sequence： dendrites→→banded cellular dendrites→elongated cells and part of dendrites→main elongated cells and little dendrites. Moreover, the present microstructure is not normal microstructure as we saw before. Further, according to the experimental phenomenon, the dendrite to cell transition was studied theoretically. Dendrite tip shape is an important parameter to characterize the dendrite to cell transition. As the dendrite to cell transition is far from equilibrium solidification, non-equilibrium solidification is taken into consideration in calculation. Finally, it is speculated that the dendrite to cell transition would occur at the minimum tip radius.采用定向凝固方法研究Al－1．5％Cu合金枝晶一胞晶转变界面形态演化。结果表明，与以往的演化规律不同，凝固组织演化是逐步进行的，在抽拉速率为30～1500μm／s的范围内，凝固组织呈现多样化。枝晶－胞晶转变规律如下：枝晶→条带胞状枝晶→细长型胞晶和枝晶的混合组织→细长型胞晶占主导的胞枝混合组织。根据这种现象，进一步从理论方面研究枝晶－胞晶转变。枝晶尖端形状是枝晶→胞晶转变的重要参数，由于枝晶－胞晶转变偏离平衡凝固，因此，在计算过程中考虑非平衡凝固，得到枝晶－胞晶转变发生在尖端半径最小处。

关 键 词：Al-Cu alloy dendrite to cell transition directional solidification pulling rate interface morphology 

分 类 号：TG292[金属学及工艺—铸造]