3D Visualization of Morphological Evolution of Large Defects during Spark Plasma Sintering of Alumina Granules
3D Visualization of Morphological Evolution of Large Defects during Spark Plasma Sintering of Alumina Granules
复制标题
氧化铝颗粒火花等离子烧结过程中大缺陷形态演变的 3D 可视化
DOI：
10.1002/adem.202201534
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发表时间：
2023
影响因子：
3.6
通讯作者：
Wakai Fumihiro
中科院分区：
文献类型：
--
作者：
Okuma Gaku;Endo Masaya;Minagawa Haruki;Inoue Ryo;Kakisawa Hideki;Kohata Takuma;Osada Toshio;Yamamoto Takafumi;Azuma Masaki;Takeuchi Akihisa;Uesugi Masayuki;Guillon Olivier;Wakai Fumihiro
通过喷雾干燥颗粒的放电等离子烧结（SPS），必须确保产品的机械可靠性，以扩大规模和生产复杂形状的部件。在1300 °C下氧化铝颗粒的SPS过程中，通过使用同步辐射X射线多尺度层析成像研究了控制机械强度的孔隙和缺陷形态的演变。虽然无压烧结不能去除分级颗粒堆积结构产生的大缺陷，但在高于30和50 MPa的应力下，SPS几乎消除了裂纹状缺陷和分支棒状缺陷。但是，即使在50 MPa的压力下，也不能去除可能由颗粒的聚集体或凹坑产生的小的椭圆形多孔区域。使用micro-CT也发现了非常大的缺陷。据推测，这种缺陷是由松散堆积的颗粒中的大空隙形成的。通过基于烧结连续介质理论的理论预测解释了大空洞的收缩和裂纹状缺陷的消除。
The mechanical reliability of products must be assured for scaling up and production of complex‐shaped components by spark plasma sintering (SPS) of spray‐dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X‐ray multiscale tomography during SPS of alumina granules at 1300 °C. While large defects arising from the hierarchical granule packing structure cannot be removed by pressureless sintering, crack‐like defects and branched rodlike defects are almost eliminated by SPS at stresses higher than 30 and 50 MPa, respectively. But, small ellipsoidal porous regions, which may arise from aggregates or dimples of granules, cannot be removed even at a pressure of 50 MPa. A very large defect is also found by using micro‐CT. It is supposed that this defect is formed from a large void in loosely packed granules. The shrinkage of large voids and the elimination of crack‐like defects are explained by the theoretical prediction based on the continuum theory of sintering.