In situ observation of hot tearing formation in succinonitrile-acetone
In situ observation of hot tearing formation in succinonitrile-acetone
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DOI：
10.1016/s1359-6454(01)00013-1
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发表时间：
2001-04-19
期刊：
影响因子：
9.4
通讯作者：
Rappaz, M
中科院分区：
文献类型：
--
作者：
Farup, I;Drezet, JM;Rappaz, M
在丁二腈-丙酮合金的凝固过程中，用拉杆横向拉动柱状枝晶，诱发了热裂。糊状区（热裂）的打开总是发生在晶界处。在低的固体体积分数下，开口可以由更贫溶质的枝晶间液体（即，“治愈”的热泪）。当固相体积分数较高时，裂纹直接在枝晶间液相中形核或由凝固收缩引起的微孔发展而来。它们的表面（边缘）由二次枝晶臂组成，尚未桥接，但也观察到一些尖峰。这些后来的尖峰或者通过在拉伸之前跨越晶界建立的固体桥的颈缩形成，或者通过在拉伸期间液体Blm的突然破裂形成。通过扫描电子显微镜在铝铜合金的表面也发现了类似的尖峰。(C)2001由Elsevier Science Ltd代表Acta Materialia Inc.出版。
Hot tears have been induced during the solidification of a succinonitrile-acetone alloy by pulling the columnar dendrites in the transverse direction with a pulling stick. The opening of the mushy zone (hot tears) always occurred at grain boundaries. At low volume fraction of solid, the: opening can be compensated by leaner-solute interdendritic liquid (i.e., "healed" hot tears). At higher volume fraction of solid, hut tears directly nucleate in the interdendritic liquid or develop from pre-existing micropores induced by solidification shrinkage. Their surface (edge) is made of secondary dendrite arms, which have not yet bridged, but a few spikes have also been observed. These later spikes formed either by the necking of solid bridges established across the grain boundaries prior to pulling, or by the sudden break-up of the liquid Blm during pulling. Similar spikes have been found by SEM on the hut lear surface of an aluminium-copper alloy. (C) 2001 Published by Elsevier Science Ltd on behalf of Acta Materialia Inc.