Aluminum integral foam castings with microcellular cores by nano-functionalization
Aluminum integral foam castings with microcellular cores by nano-functionalization
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DOI：
10.1007/s10853-013-7668-z
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发表时间：
2013
影响因子：
4.5
通讯作者：
J. Hartmann;C. Blümel;S. Ernst;Tobias Fiegl;Karl-Ernst Wirth;C. Körner
中科院分区：
文献类型：
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作者：
J. Hartmann;C. Blümel;S. Ernst;Tobias Fiegl;Karl-Ernst Wirth;C. Körner
本工作的目的是细化铝整体泡沫铸件的孔隙形态。整体发泡成型是一种改进的高压压铸工艺，将熔体和发泡剂颗粒（氢化镁，MgH 2）的混合物以高速注入永久钢模具中。在模具表面，由于高固化速率，发泡剂的分解和孔形成被抑制，而芯的固化慢得多，从而允许发泡剂分解、孔成核和生长。发泡剂颗粒不仅作为气体供应者，而且还代表孔核。因此，可以通过增加MgH 2颗粒的数量来获得微孔泡沫芯.但是通过粉末研磨增加粉末颗粒的数量强烈地降低了流动性，并且由于增加的内聚力而导致的强烈的颗粒团聚导致不均匀的泡沫。粉末的流动性可以通过用SiO2-纳米颗粒涂覆而恢复，从而导致均匀的微孔泡沫形态。
The goal of the present work is the refinement of the pore morphology of aluminum integral foam castings. Integral foam molding, a modified high pressure die casting process, is used where a mixture of melt and blowing agent particles (magnesium hydride, MgH 2) is injected at high velocity into a permanent steel mold. At the mold surface, decomposition of the blowing agent and pore formation is suppressed due to the high solidification rate whereas solidification of the core is much slower allowing blowing agent decomposition, pore nucleation, and growth. Blowing agent particles not only act as gas suppliers but also represent pore nuclei. Thus, microcellular foam cores can be attained by increasing the number of MgH 2 particles. But increasing the number of powder particles by powder milling strongly decreases the flowability and strong particle agglomeration as a result of the increasing cohesive forces leads to inhomogeneous foams. Flowability of the powder can be restored by coating it with SiO 2-nano-particles resulting in a homogeneous microcellular foam morphology.