N. Wang and B. Wei (Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)(Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The Ag-50wt%Cu hypereutectic alloy was solidified in a 3m drop tube. It is .revealed that with the decrease of droplet size, the strnctural morphology transformed from the dendrites with long trunk and thin short secondary arms to fine dendritic structures.The calculations based on LKT dendritic growth model indicate that dendritic growth is dominantly controlled by solute diffusion within the whole undcreooling regime.However, the influence of thermal diffusion-controlled growth becomes stronger above a critical undercooling about 268K. The refinement of dendritic structure is caused by large amounts of nuclei within droplet. Moreover, it is estimated that when droplet diameter is smaller than 300μm, the undercooling and growth velocity are fanger than 268K and 290mm/s respectively, while the solute impping effect may occur. Compared with Ag-15wt%Cu hypoeutectic alloy, there is no evident feature of dendritic-toequiaxed transition for Ag-50wt%Cu hypereutectic alloy, which is consistent with the calculation results of dendritic breakap time.Keuwords: Ag-Cu alloy; rapid solidification; undercooling; dendritic growth
关键词:
Ag-Cu alloy
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null
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null
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null
刘伟
,
刘文
,
吴喜龙
,
方卫
,
徐光
,
李光俐
,
任传婷
贵金属
建立了测定银铜合金中铅、锌、镉含量的电感耦合等离子体原子发射光谱法(ICP-AES 法)，方法简便、快速，灵敏度和重现性好。根据该方法的原理建立数学模型，分析了该方法测定过程中的不确定度来源，并计算了各标准不确定度分量，以及合成标准不确定度和扩展不确定度。结果表明，影响测定结果可靠程度的主要原因是样品处理中测定元素分离富集的回收率。
关键词:
分析化学
,
ICP-AES
,
银铜合金
,
铅
,
锌
,
镉
,
不确定度
