In situ synchrotron tomographic quantification of granular and intragranular deformation during semi-solid compression of an equiaxed dendritic Al-Cu alloy
In situ synchrotron tomographic quantification of granular and intragranular deformation during semi-solid compression of an equiaxed dendritic Al-Cu alloy
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DOI：
10.1016/j.actamat.2014.05.035
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发表时间：
2014-09-01
期刊：
影响因子：
9.4
通讯作者：
Lee, P. D.
中科院分区：
文献类型：
--
作者：
Cai, B.;Karagadde, S.;Lee, P. D.
半固态变形机制在从挤压铸造到岩浆流动的一系列制造和自然现象中是重要的。使用快速同步辐射X射线断层扫描和一个定制的精密热机械装置，我们进行了四维（3-D加时间）的定量研究等轴树枝状三相材料的颗粒行为。该方法产生了对A1-15 wt.%合金在等温半固态压缩（类似于30%液体部分）期间损伤形成的新见解。铜合金在宏观和微观水平。观察到颗粒重排，如平移和旋转，并导致局部双折射。富Cu的晶间液体流入膨胀的间隙中导致液体分数的局部增加，随后在-6.4%的临界轴向应变以上快速空隙增长。使用数字体积相关性对局部法向应变和剪切应变分布进行量化，以识别塑性剪切带。在微观结构水平上，单个晶粒也被视为经历晶内变形，导致弯曲和断裂的枝晶晶粒联锁。(C)2014 Acta Materialia Inc.出版社：Elsevier Ltd
Semi-solid deformation mechanisms are important in a range of manufacturing and natural phenomena, which range from squeeze casting to magma flows. Using fast synchrotron X-ray tomography and a bespoke precision thermomechanical rig, we performed a four-dimensional (3-D plus time) quantitative investigation of the granular behaviour of equiaxed dendritic three-phase materials. This methodology produced new insights into the formation of damage during the isothermal semi-solid compression (similar to 30% liquid fraction) of an A1-15 wt.%Cu alloy at both a macroscopic and microscopic level. Grain rearrangements, such as translation and rotation, were observed and lead to local dilatancy. The resulting flow of Cu-rich intergranular liquid into the dilated interstices gave rise to a local increase in liquid fraction, followed by rapid void growth above a critical axial strain of -6.4%. The local normal and shear strain distributions were quantified using digital volume correlation, identifying dilatant shear bands. At a microstructural level, the individual grains were also seen to undergo intragranular deformation, leading to bending and fragmentation of dendrites as grains interlock. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd.