Residual Area Max Depth Model for Nanoindentation Hardness Size Effect of Single Crystal Silicon

2007 ◽  
Vol 339 ◽  
pp. 389-394
Author(s):  
L. Zhou ◽  
Ying Xue Yao ◽  
Shahjada Ahmed Pahlovy

In material nanoindentation hardness testing, the hardness will decrease with the indentation depth or peak load increase, i.e. indentation size effect (ISE). There are several models and equations were proposed to describe ISE. But the variables self-inaccurate in these models and equations, it will affect the result trueness. Single crystal silicon was used for nanoindentation experiments, and max depths were obtained from these experiments. Combining Matlab software, residual areas were obtained by atomic force microscopy (AFM). Based on max depth and residual area, a new model—residual area max depth model was proposed for indentation size effect in nanoindentaion hardness. The new model perhaps can understand and describe ISE in indentation hardness better than other models and equations.

2007 ◽  
Vol 10-12 ◽  
pp. 327-330 ◽  
Author(s):  
L. Zhou ◽  
Ying Xue Yao ◽  
Qiang Liu

Aiming at the influence law of indenter tip radius to indentation hardness, testing on the hardness of single-crystal silicon was carried out based on nanoindentation technique. Two kinds of Berkovich indenter with radius 40nm and 60nm separately were used in this experiment. According to the load-depth curve, the hardness of single-crystal silicon was achieved by Oliver-Pharr method. Experimental results are presented which show that indenter tip radius influence the hardness, the hardness value increases and the indentation size effect becomes obvious with the increasing of tip radius under same indentation depth.


2008 ◽  
Vol 392-394 ◽  
pp. 267-270
Author(s):  
Qiang Liu ◽  
Ying Xue Yao ◽  
L. Zhou

Nanoindentation device has the ability to make the load-displacement measurement with sub-nanometer indentation depth sensitivity, and the nanohardness of the material can be achieved by the load-displacement curve. Aiming at the influence law of indenter tip radius to indentation hardness, testing on the hardness of single-crystal silicon were carried out with the new self-designed nanohardness test device based on nanoindentation technique. Two kinds of Berkovich indenter with radius 40nm and 60nm separately were used in this experiment. According to the load-depth curve, the hardness of single-crystal silicon was achieved by Oliver-Pharr method. Experimental results are presented which show that indenter tip radius do influence the hardness, the hardness value increases and the indentation size effect (ISE) becomes obvious with the increasing of tip radius under same indentation depth.


1995 ◽  
Vol 10 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
M. Atkinson

The variation of apparent hardness observed in previously reported Vickers indentation tests of metals is reexamined. Common deseriptions of the effect are shown to be inaccurate: the variation of apparent hardness is monotonic but not simple. The effect is consistent with varying size of a previously postulated “plastic hinge” at the perimeter of the indent. This complexity confers uncertainty on the estimation of characteristic macrohardness from small scale tests. Association of the indentation size effect with friction and with strain hardening is confirmed.


1995 ◽  
Vol 389 ◽  
Author(s):  
S.-H. Yang ◽  
S. Morris ◽  
S. Tian ◽  
K. Parab ◽  
A. F. Tasch ◽  
...  

ABSTRACTIn this paper is reported the development and implementation of a new local electronic stopping model for arsenic ion implantation into single-crystal silicon. Monte Carlo binary collision (MCBC) models are appropriate for studying channeling effects since it is possible to include the crystal structure in the simulators. One major inadequacy of existing MCBC codes is that the electronic stopping of implanted ions is not accurately and physically accounted for, although it is absolutely necessary for predicting the channeling tails of the profiles. In order to address this need, we have developed a new electronic stopping power model using a directionally dependent electronic density (to account for valence bonding) and an electronic stopping power based on the density functional approach. This new model has been implemented in the MCBC code, UT-MARLOWE The predictions of UT-MARLOWE with this new model are in very good agreement with experimentally-measured secondary ion mass spectroscopy (SIMS) profiles for both on-axis and off-axis arsenic implants in the energy range of 15-180 keV.


Author(s):  
Nguyen Ngoc Vinh ◽  
Vu Quoc Anh ◽  
Hong Tien Thang

In this paper, the continuous stiffness measurement (CSM) indentation is employed to investigate fatigue mechanical properties of structural steel under cyclic loading. For this purpose, several representative analytical approaches were introduced to estimate the basic mechanical properties including Young’s modulus and indentation hardness from the characteristics of the loading/unloading curves. Several experiments including CSM nanoindentation, low-cycle fatigue experiment for four strain amplitude levels, optical microscope (OM), and transmission electron microscopy (TEM) examinations were conducted to observe the variation characteristics of mechanical properties at the microscale and their micro-mechanisms. The microstructural evolution of the specimens deformed by the low-cycle fatigue was observed using the OM and TEM examinations. The standard nanoindentation experiments were then performed at different strain rate levels to characterize the influences of strain rate indentation on hardness of the material. The micro-mechanisms established based on the microstructural evolution and strain gradient plasticity theory were introduced to be responsible for the variation of indentation hardness under cyclic loading. Finally, the indentation size effect (ISE) phenomenon in SS400 structural steel was investigated and explained through the strain gradient plasticity theory regarding geometrically necessary dislocations underneath the indenter tip. The experimental results can be used for practical designs as well as for understanding the fatigue behavior of SS400 structural steel. Keywords: cyclic loading; fatigue; nanoindentation; indentation size effect; strain rate sensitivity; structural steel.


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