scholarly journals Substrate effects on indentation plastic zone development in thin soft films

2001 ◽  
Vol 16 (11) ◽  
pp. 3150-3157 ◽  
Author(s):  
D. E. Kramer ◽  
A. A. Volinsky ◽  
N. R. Moody ◽  
W. W. Gerberich
Keyword(s):  
Plastic Zone ◽  
Plastic Zone Size ◽  
Contact Radius ◽  
Force Microscopy ◽  
Atomic Force ◽  
Film Hardness ◽  
Substrate Properties ◽  
Zone Development ◽  
Hardness Model ◽  
Zone Radius

Plastic zone evolution in Al–2 wt% Si metal films on silicon and sapphire substrates was studied using nanoindentation and atomic force microscopy (AFM). AFM was used to measure the extent of plastic pileup, which is a measure of the plastic zone radius in the film. It was found that the plastic zone size develops in a self-similar fashion with increasing indenter penetration when normalized by the contact radius, regardless of film hardness or underlying substrate properties. This behavior was used to develop a hardness model that uses the extent of the plastic zone radius to calculate a core region within the indenter contact that is subject to an elevated contact pressure. AFM measurements also indicated that as film thickness decreases, constraint imposed by the indenter and substrate traps the film thereby reducing the pileup volume.

Microscopy and microindentation mechanics of single crystal Fe−3 wt. % Si: Part I. Atomic force microscopy of a small indentation

1993 ◽  
Vol 8 (6) ◽  
pp. 1291-1299 ◽  
Author(s):  
S. Harvey ◽  
H. Huang ◽  
S. Venkataraman ◽  
W.W. Gerberich
Keyword(s):  
Plastic Zone ◽  
Single Crystal ◽  
Surface Displacement ◽  
Plastic Zone Size ◽  
Force Microscopy ◽  
Elastic Plastic ◽  
Atomic Force ◽  
Plastic Indentation ◽  
Volume Estimates ◽  
Small Indentation

Atomic force microscope measurements of elastic-plastic indentation into an Fe−3 wt. % Si single crystal showed that the volume displaced to the surface is nearly equal to the volume of the cavity. The surface displacement profiles and plastic zone size caused by a 69 nm penetration of a Vickers diamond tip are reasonably represented by an elastic-plastic continuum model. Invoking conservation of volume, estimates of the number of dislocations emanating from the free surface are reasonably consistent with the number of dislocations that have formed in the plastic zone to represent an average calculated plastic strain of 0.044.

Plastic Zone Development Around Nanoindentations

2000 ◽  
Vol 649 ◽  
Author(s):  
C. L. Woodcock ◽  
D. F. Bahr ◽  
N. R. Moody
Keyword(s):  
Plastic Zone ◽  
Peak Load ◽  
Contact Radius ◽  
Length Scale ◽  
Bcc Metals ◽  
Cube Corner ◽  
Zone Development ◽  
Definition Of ◽  
Zone Radius ◽  
Indenter Geometry

ABSTRACTJohnson's cavity model relating indenter geometry and deformation resulting from elastic-plastic indentations is appropriate for a wide variety of materials. In the case of nanoindentations in single crystal BCC metals, limitations are reached when creep is not fully accounted for. Both the standard Berkovich and cube corner geometries show that the ratio of plastic zone radius to contact radius increases with the duration of time at the peak load. Indenter tip geometry is shown to play an important role in this phenomenon. Length scale phenomena, such as the indentation size effect, are also subject to various interpretations. The traditional definition of hardness does not produce similar trends with indentation length scale between the blunt Berkovich geometry and the sharper cube corner tip. However, the ratio of plastic zone radius to contact radius proves to be a tip geometry independent method of assessing the plasticity of these metals.

Substrate effects on nanoindentation mechanical property measurement of soft films on hard substrates

1999 ◽  
Vol 14 (1) ◽  
pp. 292-301 ◽  
Author(s):  
T. Y. Tsui ◽  
G. M. Pharr
Keyword(s):  
Elastic Modulus ◽  
Measurement Techniques ◽  
Substrate Effects ◽  
Aluminum Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Film Hardness ◽  
Nanoindentation Measurement ◽  
Property Measurement ◽  
Sputter Deposited

Substrate effects on the measurement of thin film mechanical properties by nanoindentation methods have been studied experimentally using a model soft film on hard substrate system: aluminum on glass. The hardness and elastic modulus of aluminum films with thicknesses of 240, 650, and 1700 nm sputter-deposited on glass were systematically characterized as a function of indenter penetration depth using standard nanoindentation methods. Scanning electron and atomic force microscopy of the hardness impressions revealed that indentation pileup in the aluminum is significantly enhanced by the substrate. The substrate also affects the form of the unloading curve in a manner that has important implications for nanoindentation data analysis procedures. Because of these effects, nanoindentation measurement techniques overestimate the film hardness and elastic modulus by as much as 100% and 50%, respectively, depending on the indentation depth. The largest errors occur at depths approximately equal to the film thickness.

Fatigue Microcrack Plastic Zone Size Determination

2005 ◽  
Vol 475-479 ◽  
pp. 4145-4148
Author(s):  
Tamaz Eterashvili ◽  
M. Vardosanidze
Keyword(s):  
Plastic Zone ◽  
Simple Formula ◽  
Elasticity Modulus ◽  
Plastic Zone Size ◽  
Austenitic Steels ◽  
Zone Size ◽  
Interference Microscope ◽  
Linear Elastic ◽  
Zone Radius ◽  
Good Agreement

The microcrack tip plastic zone sizes in austenitic steels are measured using REM and interference microscope. It is shown that the plastic zone size varies from 300µm to 350µm. The importance of determining this parameter is discussed. Based on the analysis of the conventional continuum equations of linear-elastic approach a simple formula is derived for calculation of plastic zone size, R=d E/2π σF, establishing relation between the plastic zone radius (R), microcrack width (d), elasticity modulus (E) and the yield strength of the material (σF). The measured values of plastic zone size are in a good agreement with those reported in literature, and calculated by the above formula.

Demonstration of Defect-Induced Limitations on the Properties of Au/3C-SiC Schottky Barrier Diodes

2009 ◽  
Vol 156-158 ◽  
pp. 331-336 ◽  
Author(s):  
Jens Eriksson ◽  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Stefano Leone ◽  
...  
Keyword(s):  
Contact Area ◽  
Schottky Diodes ◽  
Electrical Current ◽  
Contact Radius ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Capacitance Voltage

The electrical current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/3C-SiC Schottky diodes were studied as a function of contact area. The results were correlated to defects in the 3C-SiC, which were studied and quantified by conductive atomic force microscopy (C-AFM). A method based on C-AFM was introduced that enables current-voltage characterization of diodes of contact radius down to 5 µm, which consequently allows the extraction of diode parameters for Schottky diodes of very small contact area.

Nanomechanical Properties of SiC Films Grown From C60 Precursors Using Atomic Force Microscopy

1997 ◽  
Vol 119 (1) ◽  
pp. 26-30 ◽  
Author(s):  
K. Morse ◽  
T. P. Weihs ◽  
A. V. Hamza ◽  
M. Balooch ◽  
Z. Jiang ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Silicon Nitride ◽  
Friction Coefficient ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Film Hardness ◽  
Sic Film ◽  
Sic Films

The mechanical properties of SiC films grown via C60 precursors were determined using atomic force microscopy (AFM). Conventional silicon nitride and diamond-tipped steel AFM cantilevers were employed to determine the film hardness, friction coefficient, and elastic modulus. The hardness is found to be 26 GPa by nanoindentation of the film with a Berkovich diamond tip. The friction coefficient for the silicon nitride tip on the SiC film is about one half to one third that for silicon nitride sliding on a silicon substrate. By combining nanoindentation and AFM measurements an elastic modulus of ~300 GPa is estimated for these SiC films.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

AFM study of the dynamics of α-alumina surface faceting during high-temperature processing

1995 ◽  
Vol 53 ◽  
pp. 334-335 ◽  
Author(s):  
Michael W. Bench ◽  
Jason R. Heffelfinger ◽  
C. Barry Carter
Keyword(s):  
High Temperature ◽  
Thin Foil ◽  
Sem Analysis ◽  
Conductive Coatings ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Formation And Evolution ◽  
High Temperature Processing ◽  
Nominal Surface

To gain a better understanding of the surface faceting that occurs in α-alumina during high temperature processing, atomic force microscopy (AFM) studies have been performed to follow the formation and evolution of the facets. AFM was chosen because it allows for analysis of topographical details down to the atomic level with minimal sample preparation. This is in contrast to SEM analysis, which typically requires the application of conductive coatings that can alter the surface between subsequent heat treatments. Similar experiments have been performed in the TEM; however, due to thin foil and hole edge effects the results may not be representative of the behavior of bulk surfaces.The AFM studies were performed on a Digital Instruments Nanoscope III using microfabricated Si3N4 cantilevers. All images were recorded in air with a nominal applied force of 10-15 nN. The alumina samples were prepared from pre-polished single crystals with (0001), , and nominal surface orientations.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

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