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利用同步辐射装置的SR-CT,通过图像的断层扫描及3D重建,对轧制复合-粉末冶金发泡工艺制备的泡沫铝夹芯板(AFS)进行了泡孔结构演化的研究,分析了发泡过程中孔隙率的变化及大尺寸连通孔的形成原因。研究结果表明:具有微米级空间分辨率的SR-CT可清晰地观测到泡孔萌生及生长各阶段的泡沫结构。泡孔在发泡15~30 s阶段生成,形状为垂直于轧制方向的类裂纹孔。发泡45 s时,泡孔开始发生明显合并,继续延长发泡时间易导致形成大尺寸连通孔。芯层泡沫铝的孔隙率在泡孔的萌生阶段及合并阶段增长幅度较大,减少混料时发泡剂的“团聚”及提高芯层粉末致密度可获得良好的芯层泡沫结构。
The SR-CT of synchrotron radiation device was used to study the evolution of cell structure of foam aluminum sandwich panel (AFS) prepared by rolling composite-powder metallurgy foaming process through tomographic scanning and 3D reconstruction. The change of porosity in the process of foaming and the reason of the formation of large-size communicating holes. The results show that SR-CT with micron-scale spatial resolution can clearly observe the foam structure at various stages of cell initiation and growth. Foam in the bubble 15 ~ 30 s stage generated, the shape perpendicular to the rolling direction of the crack-like holes. Foaming 45 s, the cell began to significantly merge, continue to extend the foaming time easily lead to the formation of large-size communication holes. The porosity of the core foam aluminum in the cell initiation phase and the merger phase of growth rate is larger, reducing the mixture of the blowing agent “agglomeration ” and improve the core powder density can get a good core foam structure.