Length-scale-based hardening model for ultra-small volumes

2004 ◽  
Vol 19 (10) ◽  
pp. 2812-2821 ◽  
Author(s):  
J.M. Jungk ◽  
W.M. Mook ◽  
M.J. Cordill ◽  
M.D. Chambers ◽  
W.W. Gerberich ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Nanoparticles ◽  
Indentation Size Effect ◽  
Back Stress ◽  
Length Scale ◽  
Copper Films ◽  
Indentation Size ◽  
Composite Effect ◽  
Hardening Behavior ◽  
Surface Length

Understanding the hardening response of small volumes is necessary to completely explain the mechanical properties of thin films and nanostructures. This experimental study deals with the deformation and hardening response in gold and copper films ranging in thickness from 10 to 400 nm and silicon nanoparticles with particle diameters less than 100 nm. For very thin films of both gold and copper, it was found that hardness initially decreases from about 2.5 to 1.5 GPa with increasing penetration depth. Thereafter, an increase occurs with depths beyond about 5–10% of the film thickness. It is proposed that the observed minima are produced by two competing mechanisms. It is shown that for relatively deep penetrations, a dislocation back stress argument reasonably explains the material hardening behavior unrelated to any substrate composite effect. Then, for shallow contacts, a volume-to-surface length scale argument relating to an indentation size effect is hypothesized. A simple model based on the superposition of these two mechanisms provides a reasonable fit to the experimental nanoindentation data.

Indentation Size Effect on Hardness of Nanostructured Thin Films

2006 ◽  
Vol 312 ◽  
pp. 363-368 ◽  
Author(s):  
Chun Sheng Lu ◽  
Yiu Wing Mai ◽  
Yao Gen Shen
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Grain Boundary ◽  
Size Effect ◽  
Indentation Depth ◽  
Indentation Size Effect ◽  
Indentation Size ◽  
Nanostructured Thin Films ◽  
Measured Hardness

Based on nanoindentation techniques, the evaluation of hardness of two nanostructured thin films, AlN and Ti-Al-N, is discussed. In the case of AlN films, the indentation size effect of hardness can be modeled using the concept of geometrically necessary dislocations, whereas in the case of Ti-Al-N films, the measured hardness increases exponentially as the indentation depth decreases. The results show that, as thin films approach superhard, dislocation-based plastic deformation is gradually replaced by grain-boundary mediated deformation.

scholarly journals Temperature dependence of the indentation size effect

2010 ◽  
Vol 25 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
Oliver Franke ◽  
Jonathan C. Trenkle ◽  
Christopher A. Schuh
Keyword(s):  
High Temperature ◽  
Size Effect ◽  
Temperature Dependence ◽  
Thermal Activation ◽  
Indentation Size Effect ◽  
Inert Atmosphere ◽  
Length Scale ◽  
Indentation Size ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

The influence of temperature on the indentation size effect is explored experimentally. Copper is indented on a custom-built high-temperature nanoindenter at temperatures between ambient and 200 °C, in an inert atmosphere that precludes oxidation. Over this range of temperatures, the size effect is reduced considerably, suggesting that thermal activation plays a major role in determining the length scale for plasticity.

Experimental Study on the Nanoindentation of Thin Copper Films from Deep Submicron to Nano-Scale

2012 ◽  
Vol 28 (3) ◽  
pp. 507-511 ◽  
Author(s):  
Y.-R. Jeng ◽  
C.-M. Tan ◽  
C. C. Su ◽  
S.-C. Cheng ◽  
C.-Y. Cheng
Keyword(s):  
Thin Films ◽  
Composite System ◽  
Indentation Size Effect ◽  
Single Crystal Silicon ◽  
Deep Submicron ◽  
Substrate Effect ◽  
Copper Films ◽  
Pmma Substrate ◽  
Soft Substrate ◽  
Crystal Silicon

AbstractThis study uses the nanoindentation technique to evaluate the mechanical properties of thin copper films at indentation depths measured in the order of nanometers. Copper films with various thicknesses are deposited on a single crystal silicon wafer with a (100) orientation and on a polymethylmethacrylate (PMMA) substrate, respectively. The experimental results show that for soft thin films on a hard substrate, the substrate effect is negligible when the indentation depth is less than 20% of the film thickness. However, the results suggest that hard films on a soft substrate should be treated as a composite system in indentation because the substrate effect is significant. Finally, the results reveal that a significant indentation size effect exists for thin films with a thickness of less than 100nm. A number of possible reasons for the depth dependence of the hardness properties at ultra-shallow indentation depths are proposed and discussed.

Indentation and Finite Element Modelling Investigations of the Indentation Size Effect in Aluminium Coatings on Borosilicate Glass Substrates

2003 ◽  
Vol 795 ◽  
Author(s):  
I. Spary ◽  
N. M. Jennett ◽  
A. J. Bushby
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Size Effect ◽  
Yield Stress ◽  
Borosilicate Glass ◽  
Quantitative Methods ◽  
Indentation Size Effect ◽  
Surface Profile ◽  
Indentation Size ◽  
Plastic Properties

ABSTRACTNanoindentation is one of the few available methods and the most commercially widespread technique for investigating the elastic and plastic properties of small volumes such as thin films. Quantitative methods for obtaining the indentation (plane strain) modulus and hardness of a coating have been published and finite element models (FEM) of the elastic-plastic response of indentation have been developed. Comparison of the FEM output with actual indentation data has shown that, as the indentation size reduces, the apparent yield stress of the material increases. We have shown that the increase in yield stress is predictable and falls on a master curve (MRS Symp. Proc., Vol 788, p123, 2003). Predictions have been tested and agree for a range of metals (Cu, Al, W, Ir). This points to there being a fundamental length scale for dislocation-based deformation and raises the question as to whether the yield stress of thin films may be altered by reducing thickness. This study therefore investigates the indentation response of Al coatings on Borosilicate glass as a function of coating thickness and indentation depth. FEM of the indentation contact will be compared with indentation data and AFM measurements of the surface profile to investigate the relative contributions of the indentation size effect and the effect of hardening due to the additional constraint of substrate proximity to the plastic zone.

Effects of Thickness and Indenter Geometry in Nanoindentation of Nickel Thin Films

2003 ◽  
Vol 795 ◽  
Author(s):  
Padma Parakala ◽  
Reza A. Mirshams ◽  
Seifollah Nasrazadani ◽  
Kun Lian
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Indentation Size Effect ◽  
Deformation Mechanisms ◽  
Indentation Size ◽  
Depth Of Penetration ◽  
Nickel Thin Films ◽  
Cube Corner ◽  
Depth Effects ◽  
Indenter Geometry

ABSTRACTEffects of thickness and tip geometry on Ni thin films deposited on Cu substrate were studied using nanoindenter. The deformation mechanisms in correlation to hardness measurements were discussed at various loads and depths of penetration. The Berkovich, Cube corner and Conical tips have been used in this study. Initially, the hardness and modulus of elasticity were measured at a depth of 10% of film thickness. The depth of penetration was increased to 20% to observe the depth effects. Analysis of data showed that there is an Indentation Size Effect (ISE) irrespective of indenter tip geometries.

An Investigation of Film Thickness Effect on Mechanical Properties of Au Films Using Nanoindentation Techniques

2005 ◽  
Vol 875 ◽  
Author(s):  
Yifang Cao ◽  
Zong Zong ◽  
Wole Soboyejo
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Electron Beam ◽  
Film Thickness ◽  
Size Effects ◽  
Experimental Studies ◽  
Thickness Effect ◽  
Length Scale ◽  
Indentation Size ◽  
Au Thin Films

AbstractThis paper presents the results of nanoindentation experimental studies of Au thin films with different thicknesses. The effects of film thickness and microstructure on the hardnesses of electron-beam deposited Au films were studied in terms of Hall-Petch relationship. The effects of different thicknesses on indentation size effects (ISE) are explained within the framework of mechanism-based strain gradient (MSG) theory using the concept of microstructural length scale.

Mechanical Properties of CaF2 Single Crystal Substrates Determined from Nanoindentation Techniques

1996 ◽  
Vol 436 ◽  
Author(s):  
A. Aruga ◽  
R. B. Inturi ◽  
J. A. Barnard ◽  
R. C. Bradt
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Single Crystal ◽  
Power Law ◽  
Indentation Size Effect ◽  
Berkovich Indenter ◽  
Indentation Size ◽  
Proportional Specimen Resistance ◽  
Caf2 Single Crystal ◽  
Resistance Model

AbstractCaF2 single crystals are interesting substrate materials for deposition of thin films. Its structure is cubic and it cleaves on {111} planes. CaF2, whose hardness has been reported to be 4 on the Moh's scale, is plastic and soft. In this study, the mechanical properties such as hardness(H) and Young's modulus(E) of single crystal CaF2 mineral were measured by using a nanoindenter with a Berkovich indenter normal to (100) and (111) planes. A normal indentation size effect (ISE) in accordance with the traditional power law and the proportional specimen resistance model (PSR) of Li and Bradt [1] was observed. The values of E and H on (100) plane are larger than those on (111) plane and these values on both planes decrease with increase in time during the hold segment. The effect of displacement rate on mechanical properties of (100) and (111) surfaces is also studied.

The Identation Size Effect and Hall-Petch Behaviour of Annealed Polycrystalline Copper

2006 ◽  
Vol 976 ◽  
Author(s):  
XiaoDong Hou ◽  
T.T. Zhu ◽  
N. M. Jennett ◽  
A. J. Bushby
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Size Effects ◽  
Indentation Size Effect ◽  
Indentation Test ◽  
Small Radius ◽  
Contact Radius ◽  
Length Scale ◽  
Indentation Size ◽  
Non Destructive

AbstractMethods to obtain tensile stress-strain properties of materials from a practically non-destructive indentation test are of great industrial interest. However, to do this successfully, indentation size effects must be accounted for. Many indentation size effects, such as strain gradient plasticity and micro-pillar experiments [1], show a size dependence proportional to the inverse square root of a length scale, in common with Hall-Petch behavior. Recently, however, the indentation size effect from small radius spherical indenters has been shown, for a range of fcc metals, not to follow a Hall-Petch-like relationship but to be proportional to the inverse cube root of indenter radius [2]. Here, we investigate these differences further and present results for the indentation size effect with spherical indenters on Cu samples that have been engineered to have different grain sizes. The important experimental control parameter of the relative size of the indentation compared to the grain size is also explored since the cross over from grains significantly smaller than the contact radius to grains significantly larger than the contact radius occurs at different length scales in each sample. A thorough understanding of the various length-scale effects in the different test methods (e.g. the indentation size effect and grain size effect in indentation), is essential if a relationship, robust enough for industrial application, is to be defined to obtain tensile properties from an essentially non-destructive indentation test.

scholarly journals Investigation of the mechanism of the indentation size effect for titanium

2019 ◽  
Vol 6 (2) ◽  
pp. 18-00545-18-00545
Author(s):  
Shota HASUNUMA ◽  
Hirohisa MIYAZAKI ◽  
Takeshi OGAWA
Keyword(s):  
Size Effect ◽  
Indentation Size Effect ◽  
Indentation Size
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