High-temperature strength and damage evolution in short fiber reinforced aluminum alloys studied by miniature creep testing and synchrotron microtomography
High-temperature strength and damage evolution in short fiber reinforced aluminum alloys studied by miniature creep testing and synchrotron microtomography
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DOI：
10.1016/j.actamat.2011.09.022
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发表时间：
2012-01-01
期刊：
影响因子：
9.4
通讯作者：
Eggeler, G.
中科院分区：
文献类型：
--
作者：
Kurumlu, D.;Payton, E. J.;Eggeler, G.
使用微型蠕变样品研究了挤压铸造短纤维增强铝金属基复合材料 (MMC) 的蠕变行为，该复合材料由 Al-11 wt.% Zn-0.2 wt.% Mg 合金和 15 vol.% Al2O3 Saffil (R) 短纤维增强。微型蠕变样本的小尺寸允许它们从具有不同微观结构的 MMC 块的区域进行加工，从而允许在比使用传统样本几何形状更局部的水平上研究晶粒尺寸和纤维纹理对蠕变的影响。微型蠕变样本在 573 至 623 K 之间的温度下承受 3 至 40 MPa 的单轴拉伸应力。结果表明，使用微型蠕变样本几何形状进行的测试与先前使用标准蠕变样本获得的结果非常一致。通过间断蠕变实验，观察到卸载后发生的蠕变回流随着累积塑性应变的增加而增加。在铸态MMC中，同步加速器显微断层扫描揭示了孔隙的精细分布，其空间密度随着纤维的空间密度而增加。还揭示了蠕变 MMC 中断裂纤维的存在。断裂纤维片段之间的一些区域似乎充满了基质材料，而其他区域则呈空隙。 (C) 2011 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
The creep behavior of a squeeze-cast, short fiber reinforced Al metal matrix composite (MMC), consisting of an Al-11 wt.% Zn-0.2 wt.% Mg alloy reinforced with 15 vol.% Al2O3 Saffil (R) short fibers is investigated using miniature creep specimens. The small dimensions of the miniature creep specimens permit them to be machined from regions of an MMC block with different microstructures, thus allowing the effect of grain size and fiber texture on creep to be investigated on a more local level than is possible using conventional specimen geometries. The miniature creep specimens are subjected to uniaxial tensile stresses ranging from 3 to 40 MPa at temperatures between 573 and 623 K. It is shown that tests performed using the miniature creep specimen geometry are in good agreement with results previously obtained with standard creep specimens. Through interrupted creep experiments, it is observed that the creep back flow that occurs after unloading increases with increasing accumulated plastic strain. In the as-cast MMC, synchrotron microtomography reveals a fine distribution of pores whose spatial density increases with the spatial density of the fibers. The presence of fractured fibers in the crept MMC is also revealed. Some of the regions between fractured fiber fragments appear to be filled with matrix material, while others are voided. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.