Nanoindentation Hardness Tests Using a Point Contact Microscope

1994 ◽  
Vol 116 (1) ◽  
pp. 175-180 ◽  
Author(s):  
C. J. Lu ◽  
D. Bogy ◽  
R. Kaneko
Keyword(s):  
Point Contact ◽  
Indentation Load ◽  
Apex Angle ◽  
Indentation Force ◽  
Single Leaf ◽  
Leaf Springs ◽  
Hardness Tests ◽  
Nanoindentation Hardness ◽  
Tip Radius ◽  
Hardness Values

The Point Contact Microscope (PCM), developed in NTT’s Kaneko Research Laboratory, is used to conduct hardness tests on polycarbonate and gold at indentation depths in the range of about 5-100 nm. Different diamond indenters, which are attached to single leaf springs of various stiffnesses, are used to study the effects of tip radius and apex angle on the measured hardness values. The indentation depth versus force and hardness versus force relations for various tip conditions are examined. It is found that the hardness value obtained increases for small values of indentation load and approaches a tip-independent value for larger loads. The hardness is sensitive to the indentation force and tip radius in the limit of small indentation depths. In this case, a standard indenter and a fixed load should be used to compare the hardnesses of different materials. The effect of the apex angle on the hardness is relatively insignificant.

Simplified Area Function for Sharp Indenter Tips in Depth-sensing Indentation

2002 ◽  
Vol 17 (5) ◽  
pp. 1143-1146 ◽  
Author(s):  
Jeremy Thurn ◽  
Robert F. Cook
Keyword(s):  
Cone Angle ◽  
Indentation Load ◽  
Depth Sensing ◽  
Area Function ◽  
Eden Prairie ◽  
Two Parameters ◽  
Tip Radius ◽  
Hardness Values ◽  
Effective Cone ◽  
Two Parameter

A two-parameter “area function” characterizing the depth-dependent projected area of an indenter was introduced and applied to a Berkovich tip. The two parameters have physical meaning, corresponding to the effective tip radius and effective cone angle. The indenter tip was calibrated on a commercial load-controlled Nano Indentert® XP (MTS Systems Corp., Eden Prairie, MN). All calibrations were carried out using the procedure of Oliver and Pharr [J. Mater. Res. 7, 1564 (1992)] using several homogeneous materials. Plane-strain modulus and hardness values deconvoluted from indentation load–displacement traces using the calibrated two-parameter area function compared well with the values determined using the empirical eight-parameter area function of Oliver and Pharr.

Determining Brinell Hardness From Analysis of Indentation Load-Depth Curve Without Optical Measurement

2005 ◽  
Vol 127 (1) ◽  
pp. 154-158 ◽  
Author(s):  
Sung-Hoon Kim ◽  
Eun-chae Jeon ◽  
Dongil Kwon
Keyword(s):  
Optical Measurement ◽  
Brinell Hardness ◽  
Indentation Load ◽  
Residual Lifetime ◽  
Element Analysis ◽  
Hardness Tests ◽  
The Relationship ◽  
Hardness Values ◽  
Depth Curve ◽  
Work Hardening Exponent

Hardness tests are performed to determine not only hardness but also other properties such as strength, wear resistance, and deformation resistance. They are also performed to predict residual lifetime through analysis of the hardness reduction or hardness ratio. However, hardness tests require observation of the residual indentation, and for that reason are not widely used in industrial fields. This study thus examines obtaining Brinell hardness values without optical observation, using instead quantitative formulas and analyzing the relationship between the indentation depths from the indentation load-depth curve and mechanical properties such as the work-hardening exponent, yield strength, and elastic modulus on the basis of finite-element analysis.

scholarly journals Application of the plasticity characteristic determined by the indentation technique for evaluation of mechanical properties of coatings: I. specific features of the test method procedure

2004 ◽  
Vol 36 (1) ◽  
pp. 27-41 ◽  
Author(s):  
A.V. Byakova ◽  
Yu.V. Milman ◽  
A.A. Vlasov
Keyword(s):  
Mechanical Properties ◽  
Indentation Load ◽  
Test Method ◽  
Simplified Model ◽  
Micro Hardness ◽  
Properties Of Coatings ◽  
Modified Model ◽  
Plasticity Characteristic ◽  
Measurement Results ◽  
Hardness Values

Specific features of the test method procedure capable for determining the plasticity characteristic dH by indentation of inhomogeneous coatings affected by residual stress was clarified. When the value of the plasticity characteristic for coating was found to be as great as dH > 0.5 a simplified model was found to be reasonably adequate, while a modified model assumed compressibility of the deformation core beneath indentation. The advantage of the modified approach compared to the simplified one was grounded experimentally only if the elastic deformation for coating becomes greater than ?e ? 3.5%, resulting in the decrease of plasticity characteristic dH < 0.5. To overcome non accuracy caused by the effect of the scale factor on measurement results a comparison of different coatings was suggested using stabilized values of the plasticity characteristic dH determined under loads higher than critical, P ? Pc, ensuring week dependence of micro hardness values on the indentation load.

scholarly journals Contrast Mechanism Maps for Piezoresponse Force Microscopy

2002 ◽  
Vol 17 (5) ◽  
pp. 936-939 ◽  
Author(s):  
Sergei V. Kalinin ◽  
Dawn A. Bonnell
Keyword(s):  
Piezoresponse Force Microscopy ◽  
Radius Of Curvature ◽  
Experimental Conditions ◽  
Force Microscopy ◽  
Indentation Force ◽  
Domain Structures ◽  
Contrast Mechanism ◽  
Local Modification ◽  
Tip Radius ◽  
Imaging Conditions

Piezoresponse force microscopy (PFM) is one of the most established techniques for the observation and local modification of ferroelectric domain structures on the submicron level. Both electrostatic and electromechanical interactions contribute at the tip-surface junction in a complex manner, which has resulted in multiple controversies in the interpretation of PFM. Here we analyze the influence of experimental conditions such as tip radius of curvature, indentation force, and cantilever stiffness on PFM image contrast. These results are used to construct contrast mechanism maps, which correlate the imaging conditions with the dominant contrast mechanisms. Conditions under which materials properties can be determined quantitatively are elucidated.

scholarly journals Contact Behaviour of Composite Laminate under Quasi-Static Indentation Load

2013 ◽  
Vol 577-578 ◽  
pp. 545-548
Author(s):  
Z. Shen ◽  
Y.G. Xu ◽  
Andreas Chrysanthou
Keyword(s):  
Composite Laminates ◽  
Matrix Material ◽  
Substantial Reduction ◽  
Indentation Load ◽  
Contact Behavior ◽  
Damage Initiation ◽  
Indentation Force ◽  
Contact Behaviour ◽  
Static Indentation ◽  
Engineering Alloys

A viable solution to the ever-demanding weight-saving target in aerospace industry is the replacement of conventional engineering alloys with composite materials in primary structures. A major concern to the effective use of composite laminates is the substantial reduction in the compressive strength when the contact force has exceeded the delamination threshold load (DTL). This paper focuses on the study of the contact behavior of composite laminates under quasi-static indentation (QSI) forces. The effect of damage initiation and growth on contact behavior has been investigated via detailed assessment of the relation between the indentation force and the dent depth. Different phases corresponding to undamaged, local damage, global damage, and final failure of the laminate have been identified. A modification to the classical Hertz contact law has been proposed to account for the matrix material resistance to plastic deformation.

Wear Tests and Pull-Off Force Measurements of Single Asperities by Using Parallel Leaf Springs Installed on an Atomic Force Microscope

1999 ◽  
Vol 122 (3) ◽  
pp. 639-645 ◽  
Author(s):  
Yasuhisa Ando
Keyword(s):  
Single Crystal ◽  
Adhesion Force ◽  
Normal Load ◽  
Single Crystal Silicon ◽  
Leaf Spring ◽  
Wear Volume ◽  
Crystal Silicon ◽  
Single Leaf ◽  
Leaf Springs ◽  
Gold Plate

At the micro-scale level, the adhesion force dominates the friction force when the normal load approaches zero. For determining the effects of micro wear on the adhesion (pull-off) force, the wear-induced changes in surface topography of asperities and the pull-off force between the asperities and leaf springs were determined. First, single asperities were formed on a single-crystal gold plate and the asperities were rubbed with a silicon leaf spring attached to an AFM (atomic force microscope). A focused ion beam (FIB) system was used to form gold pyramid-shaped asperities on the surface of a single crystal gold plate. The FIB was also used to create the two types of single crystal silicon leaf springs tested here; single and parallel. The single leaf spring was created by flattening the probe-head of a commercially available AFM cantilever for AC mode. The parallel leaf spring was created by removing the central portion of a single-crystal silicon beam (25 μm×50 μm×300 μm). For the single leaf spring, the pull-off force no longer increased when the sliding distance exceeded 5 mm at a load of more than 200 nN. On the other hand, for the parallel leaf spring, the pull-off force increased monotonically with sliding distance, showing a more rapid increase at the higher normal load. The worn area of the asperity peak (measured by using an ordinary AFM probe) was proportional to the pull-off force. The wear volume per unit distance (i.e., wear rate) was estimated from the change in pull-off force, and was found to increase monotonically with the external load. There was no effect of adhesion force on the wear volume. [S0742-4787(00)01102-4]

scholarly journals Caracterização metalúrgica de ligas de Ni-Cr para metalocerimica

2021 ◽  
Vol 40 (1) ◽  
pp. 57-59
Author(s):  
Carlos Ariel Samudio Perez ◽  
Cezar Augusto Garbin
Keyword(s):  
Solid Solution ◽  
Diffraction Analysis ◽  
The Other ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tests ◽  
Density Values ◽  
Cubic Structure ◽  
Hardness Values

Alternative Ni-Cr alloys applied in dentistry of two commercial brands for ceramometal restoration were evaluated. The alloys were analyzed in the commercial and after casting conditions using experimental techniques of metallography, X-ray diffraction, superficial hardness and density. The metalografics and X-ray diffraction analysis showed that, the alloys microstructure is marked with the presence of a solid solution having an ordered face- centred cubic structure, Ni-rich austenitic (y phase) matrix, and with fine precipitates particles of secondary phases. The Vicker hardness tests showed a decrease in hardness values of the studied alloys aer casting. The alloys density values, on the other hand, did not manifest changes.

scholarly journals Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites

2010 ◽  
Vol 61 (5) ◽  
pp. 305-307 ◽  
Author(s):  
Erika CsehovAaA ◽  
Jana AndrejovskAaA ◽  
Apichart Limpichaipanit ◽  
Ján Dusza ◽  
Richard Todd
Keyword(s):  
Size Effect ◽  
Vickers Hardness ◽  
Indentation Load ◽  
Proportional Specimen Resistance ◽  
Load Size ◽  
Hardness Values ◽  
True Hardness

Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites The indentation load-size effect (ISE) in Vickers hardness of Al2O3 and Al2O3 + SiC nanocomposites has been investigated and analysed using Meyer law, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The strongest ISE was found for alumina. Both the PSR and MPSR models described the ISE well, but the MPSR model resulted in slightly lower true hardness values for all materials investigated. No evidence of the effect of machining stresses on the ISE has been found.

scholarly journals Estimation of Strength Properties from Microhardness Results in Dual Phase Steels with Different Martensite Volume Fraction

2018 ◽  
Vol 47 (3) ◽  
pp. 206-212 ◽  
Author(s):  
Gábor Béres ◽  
Zoltán Weltsch
Keyword(s):  
Volume Fraction ◽  
Tensile Tests ◽  
Strength Properties ◽  
Indentation Load ◽  
Experimental Investigations ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Martensite Volume Fraction ◽  
Martensite Content ◽  
Hardness Values

This study is about the effect of the martensite volume fraction and indentation load on microhardness profiles of dissimilar types Dual Phase steels and DC04 mild steel. Experimental investigations were performed by mickrovickers method with using of eight different indentation loads from 0.01 kp up to 1 kp. Besides, microscope and tensile tests were carried out to complete the estimation.The hardness profiles show similar characteristics in case of all examined steels independent from the microstructure. In the lowest load ranges at 0.01 and 0.025 kp (HV0.01 and HV0.025), there are no appropriate approximations with the martensite volume fraction, due to the high deviation of the hardness results which caused by the little indentation geometry. In higher ranges, above 0.05 kp (HV0.05), linear evaluations could be applicable. With the utilization of the fitted parameters, a definite relationship is reported in the hardness values and even in the strength and elongation properties with the martensite content. Based on these correlations such contexts are added which make contact between microhardness and strength values for the practice. The discrepancy between the measured and calculated results stay under 10 HV which is less than 5%.

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