Nanoplastic deformation of nanoindentation: Crystallographic dependence of displacement bursts
Nanoplastic deformation of nanoindentation: Crystallographic dependence of displacement bursts
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DOI：
10.1016/j.actamat.2006.10.055
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发表时间：
2007-03
期刊：
影响因子：
9.4
通讯作者：
Y. Shibutani;T. Tsuru;Atsuhiro Koyama
中科院分区：
文献类型：
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作者：
Y. Shibutani;T. Tsuru;Atsuhiro Koyama
本文总结了单晶铝和单晶铜在（001）、（110）和（111）三种表面指数下的纳米压痕位移猝发的晶体学依赖性。结果表明，第一次位移突裂时的突裂宽度与临界突裂载荷之间的实验线性关系具有明显的晶体学依赖性。由临界剪切载荷，用Hertz接触力学估算了Al和Cu的位错形核临界剪切应力分别为3.3GPa和3.6GPa，与理想值接近。我们解释了纳米塑性力学的一个全面的能量平衡模型来描述之间的线性关系的冲击载荷和爆裂宽度，和集体位错成核模型组成的三维位错环，以评估的位错成核的数量。前者能定性地导出位错破裂宽度与位错集体滑移之间的线性关系，并能将位错破裂宽度与位错集体滑移联系起来。后者将理论临界载荷和破裂宽度与冲头半径和形核位错间距dD的函数联系起来，其中dD取10 B（B为Burgers矢量）左右，能较好地代表Al的实验数据。
The present paper summarizes the crystallographic dependence of the displacement bursts in nanoindentation using single crystalline aluminum and copper with three kinds of surface indices, namely (001), (110) and (111). It is found that the experimental linear relation between the critical indent load and the burst width of the indent depth at the first displacement burst has significant crystallographic dependence. From the critical indent loads, the critical resolved shear stresses of the dislocation nucleation were estimated to be 3.3GPa for Al and 3.6GPa for Cu, using Hertz contact mechanics, which are both close to the ideal values. We explain the nanoplastic mechanics by a comprehensive energy balance model to describe the linear relation between the indent load and the burst width, and by the collective dislocation nucleation model consisting of three-dimensional dislocation loops to evaluate the number of dislocations nucleating. The former model can derive the linear relation qualitatively and link the burst width to the collective dislocation slipping. The latter relates the theoretical critical load and burst width with the function of the punch radius and the distance between dislocations nucleating dD, in which setting dDas about 10b (b is the Burgers vector) can fairly represent the Al experimental data.