On the effect of Nb-based compounds on the microstructure of Al-12Si alloy
On the effect of Nb-based compounds on the microstructure of Al-12Si alloy
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DOI：
10.1016/j.matchemphys.2015.05.076
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发表时间：
2015-07
影响因子：
4.6
通讯作者：
L. Bolzoni;M. Nowak;N. H. Babu
中科院分区：
文献类型：
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作者：
L. Bolzoni;M. Nowak;N. H. Babu
铸造铝合金是实现汽车轻量化、减少温室气体排放和污染的重要结构材料。通过晶粒细化可以进一步改善铸造铝合金的组织和性能，这是普通Al-Ti-B晶粒细化剂不能有效地用于变形铝合金的实践。在这项工作中，我们提出了就业的Nb+B孕育作为一种替代细化初生α-Al枝晶的铸造Al-Si合金通过研究晶粒细化诱导Nb+B孕育剂作为一个功能的关键方面，如冷却速度，衰退行为和模拟再循环试验。发现Nb+B孕育材料的晶粒尺寸对冷却速率的敏感性明显降低。Nb+B孕育剂仍然存在，并且即使在几个小时的接触时间之后也促进Al-12 Si合金的细化，尽管检测到一些褪色。此外，Nb+B孕育剂在孕育合金三次重熔后仍能有效地促进异质形核。在重熔后保持晶粒细化效力的褪色行为和能力与工业规模应用高度相关。
Cast Al alloys are important structural materials for the lightweighting of cars and, consequently, reduction of greenhouse gases emission and pollution. The microstructure and properties of cast Al alloys could be further improved by means of grain refinement, practise which cannot efficiently be performed with common Al–Ti–B grain refiners used for wrought Al alloys. In this work we proposed the employment of Nb+B inoculation as an alternative for the refinement of the primary α-Al dendrites of cast Al–Si alloy by studying the grain refinement induced by the Nb+B inoculants as a function of key aspects such as cooling rate, fading behaviour and simulated recyclability tests. It is found that the grain size of the Nb+B inoculated material is noticeably less sensitive to the cooling rate. Nb+B inoculants are still present and promote the refinement of the Al–12Si alloy even after few hours of contact time, although some fading is detected. Furthermore, Nb+B inoculants are also still effective for enhancing heterogeneous nucleation after three remelting of the inoculated alloy. The fading behaviour and ability to retain grain refining potency after remelting are highly relevant to industrial scale applications.