Shear cracking in an Al powder compact studied by X-ray microtomography
Shear cracking in an Al powder compact studied by X-ray microtomography
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DOI：
10.1016/j.msea.2009.02.009
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发表时间：
2009-05-20
期刊：
影响因子：
6.4
通讯作者：
Withers, P. J.
中科院分区：
文献类型：
--
作者：
McDonald, S. A.;Motazedian, F.;Withers, P. J.
本文介绍了一种铝合金粉末压制的实验研究，以确定导致剪切裂纹的物理过程的顺序。粉末被压实在一个包含一个长长的中心垂直销的模具中。利用图像相关性，从X射线断层扫描3D体积序列中捕获的粉末中TiN标记的运动，绘制出压坯中的位移和应变模式的演变。可以观察到，压实最广泛地发生在销的上方，当粉末接近局部完全密度时，创建了基本上刚性的圆顶区域。随着压实力的进一步增加，穹顶周围发生强烈的剪切变形，将颗粒涂抹出去，导致剪切裂缝的形成。在压实不同阶段破坏性拍摄的光学显微照片清楚地显示了剪切面两侧颗粒的变形和裂纹的形态。(C)2009爱思唯尔B.V.保留所有权利。
An experimental study is presented of the compaction of an aluminium alloy powder to determine the sequence of physical processes that leads to shear cracking. The powder was compacted in a die containing a long central vertical pin. Image correlation was used to map out the evolution of the displacement and strain patterns in the compact from the motion of tin markers in the powder captured in a sequence of X-ray tomographic 3D volumes. Compaction is observed to occur most extensively above the pin, creating an essentially rigid domed region as the powder approaches full density locally. As the compaction force is increased further, intense shear deformation occurs around the dome, smearing out the particles and leading to the formation of a shear crack. Optical micrographs taken destructively at different stages of compaction show clearly the deformation of the particles either side of the shear plane and the morphology of the crack. (C) 2009 Elsevier B.V. All rights reserved.