Al-4.5Cu合金柱状晶的穗状晶生长形态及机理

Spike-like Crystals Growth Interface Morphology and Formtive Cause of Constrained Columnar Crystals on Al-4.5Cu Alloy

利用自行研制的电磁泵驱动液流定向凝固装置 ,首次成功地发现了Al- 4.5Cu合金柱状晶的穗状晶生长区域并观察到其形态 .研究发现 :穗状晶生长区域位于液流速度v >4.5cm/s,柱状晶的生长速度R为 2 0～ 80 μm/s的局部范围内 .在该区域中 ,近胞状生长区域晶体呈典型穗状迎流生长 ;近枝晶生长区域晶体近垂直生长 。

In a directional solidification instrument developed in our lab . With an electromagnetic pump , at given cooling condition, the first discovery of spike-like crystals growth interface morphology and formative conditions of Al-4.5Cu alloy has been made . Results indicate that the conditions of spike-like crystals growth are the flow velocity v>4.5 cm/s and the growth velocity 20 μm/s<R<80 μm/s . In this area , when the growth velocity is high, the crystal grows vertically bounch-like crystal ; when the growth velocity is low, the crystal grows upstream classic spike-like crystal.