Yielding behavior and its effect on uniform elongation in IF steel with various grain sizes
Yielding behavior and its effect on uniform elongation in IF steel with various grain sizes
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DOI：
10.1007/s10853-014-8233-0
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发表时间：
2014-04
影响因子：
4.5
通讯作者：
Si-feng Gao;Meichuan Chen;M. Joshi;A. Shibata;N. Tsuji
中科院分区：
文献类型：
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作者：
Si-feng Gao;Meichuan Chen;M. Joshi;A. Shibata;N. Tsuji
在本研究中，不同晶粒度的IF钢试件采用累积叠轧工艺和随后的退火工艺制备，其晶粒度在12~0.45μm之间。拉伸试验表明，通过将平均晶粒度减小到小于约1.5xμm的超细范围，IF钢的屈服行为逐渐从连续屈服转变为不连续屈服。当平均晶粒度小于约1μm时，均匀延伸率出现突变损失，对屈服应力和均匀延伸率的Hall-Petch分析表明，在超细晶粒度范围内，均匀延伸率的突变损失对应于不连续屈服行为的出现。在许多UFG材料中发现，不连续屈服被认为是UFG材料的一种独特的力学行为，对UFG材料的均匀伸长具有重要意义。
In the present study, IF steel specimens with different grain sizes ranging from 12 to 0.45 μm were fabricated by accumulative roll-bonding process and subsequent annealing. Tensile tests revealed that by decreasing the mean grain size down to an ultrafine range smaller than approximately 1.5 μm, yielding behavior of the IF steel gradually changed from continuous yielding to discontinuous yielding. An abrupt loss in the uniform elongation occurred, when the average grain size was smaller than about 1 μm. Hall–Petch analysis on the yield stress and uniform elongation implied that the abrupt loss in the uniform elongation in the UFG grain size range corresponded to the appearance of the discontinuous yielding behavior. As it has been found in many UFG materials, discontinuous yielding is believed to be a unique mechanical behavior of UFG materials, and it has significant importance on the uniform elongation of UFG materials.