Faculty of Engineering, University of Wollongong, Northfields Avenue, NSW 2522, Australia.
J Microsc. 2013 Jan;249(1):53-61. doi: 10.1111/j.1365-2818.2012.03679.x. Epub 2012 Nov 21.
Solidification microstructure is a defining link between production techniques and the mechanical properties of metals and in particular steel. Due to the difficulty of conducting solidification studies at high temperature, knowledge of the development of solidification microstructure in steel is scarce. In this study, a laser-scanning confocal microscopy (LSCM) has been used to observe in situ and in real-time the planar to cellular to dendritic transition of the progressing solid/liquid interface in low carbon steel. Because the in situ observations in the laser-scanning confocal microscopy are restricted to the surface, the effect of sample thickness on surface observations was determined. Moreover, the effect of cooling rate and alloy composition on the planar to cellular interface transition was investigated. In the low-alloyed, low-carbon steel studied, the cooling rate does not seem to have an effect on the spacing of the cellular microstructure. However, in the presence of copper and manganese, the cell spacing decreased at higher cooling rates. Higher concentrations of copper in steel resulted on an increased cell spacing at the same cooling rates.
凝固组织是连接生产技术与金属、特别是钢的力学性能的关键环节。由于在高温下进行凝固研究存在困难，因此对钢中凝固组织演变的了解还很有限。在这项研究中，我们采用激光扫描共聚焦显微镜（LSCM）实时原位观察低碳钢中从平面状到胞状再到枝晶状的凝固/液界面推进转变。由于激光扫描共聚焦显微镜的原位观察仅限于表面，因此确定了样品厚度对表面观察的影响。此外，还研究了冷却速率和合金成分对平面-胞状界面转变的影响。在所研究的低合金低碳钢中，冷却速率似乎对胞状组织的间距没有影响。然而，在存在铜和锰的情况下，较高的冷却速率会导致胞间距减小。钢中较高浓度的铜会导致在相同冷却速率下胞间距增大。
