On the effective load during nanoindentation creep testing with continuous stiffness measurement (CSM)

2021 ◽  
Author(s):  
P. Sudharshan Phani ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Creep Testing ◽  
Stiffness Measurement ◽  
Continuous Stiffness Measurement

Determination of the effective zero point of contact for spherical nanoindentation

2008 ◽  
Vol 23 (1) ◽  
pp. 204-209 ◽  
Author(s):  
Alexander J. Moseson ◽  
Sandip Basu ◽  
Michel W. Barsoum
Keyword(s):  
Accurate Determination ◽  
Zero Point ◽  
Sample Surface ◽  
Fused Silica ◽  
Contact Radius ◽  
Stiffness Measurement ◽  
Continuous Stiffness Measurement ◽  
First Contact ◽  
Versus Strain

Accurate determination of the “zero point,” the first contact between an indenter tip and sample surface, has to date remained elusive. In this article, we outline a relatively simple, objective procedure by which an effective zero point can be determined accurately and reproducibly using a nanoindenter equipped with a continuous stiffness measurement option and a spherical tip. The method relies on applying a data shift, which ensures that curves of stiffness versus contact radius are linear and go through the origin. The method was applied to fused silica, sapphire single crystals, and polycrystalline iron with various indenter sizes to a zero-point resolution of ≈2 nm. Errors of even a few nanometers can drastically alter plots and calculations that use the data, including curves of stress versus strain.

The Influence of Indentation Conditions on Nanohardness Depth Profiles of W-C Based Coatings

2014 ◽  
Vol 606 ◽  
pp. 175-178 ◽  
Author(s):  
Michal Novák ◽  
František Lofaj ◽  
Petra Hviščová
Keyword(s):  
Thin Films ◽  
Strain Rate ◽  
Measurement Method ◽  
Loading Cycle ◽  
Depth Profiles ◽  
Stiffness Measurement ◽  
Continuous Stiffness Measurement ◽  
Rate Frequency ◽  
Loading Type

The influence of different indentation parameters including loading type, loading/strain rate, frequency and amplitude on nanohardness depth profiles on DC-MS W-C based coatings thick from 300 to 850 nm were investigated with the aim to determine the best conditions for the measurement of hardness of thin films during sinusoidal loading cycle. Nanohardness tests were performed on G200 (Agilent Technologies) and NHT (CSM Instruments) nanoindenters using standard loading/unloading cycle, CMC (continuous multicycle) mode and continuous stiffness measurement method (CSM) or sinus mode, respectively. The increase of strain rate and sinus amplitude results in decrease of maxima hardness of profiles while the increase of frequency caused its increase.

Hydrogen Effect on the Deformation Behavior of Austenitic Stainless Steels Investigated by Nanoindentation

2017 ◽  
Author(s):  
Lin Zhang ◽  
Yuanjian Hong ◽  
Jinyang Zheng ◽  
Bai An ◽  
Chengshuang Zhou
Keyword(s):  
Plastic Deformation ◽  
Stainless Steels ◽  
Deformation Behavior ◽  
Austenitic Stainless Steels ◽  
Gaseous Hydrogen ◽  
Hydrogen Effect ◽  
Full Understanding ◽  
Stiffness Measurement ◽  
Initial Stage ◽  
Continuous Stiffness Measurement

A full understanding of hydrogen effect on deformation is important to reveal the mechanism of hydrogen embrittlement. The effects of thermal gaseous hydrogen charging on 304 and 310S austenitic stainless steels have been examined by using nanoindentation. It is first found by using nanoindentation continuous stiffness measurement that hydrogen decreases the elastic modulus and increases the hardness in the initial stage of plastic deformation, while the hydrogen effect becomes weaker and remains nearly constant with further plastic deformation. Hydrogen increases the creep displacement in 310S steel, which indicates that hydrogen facilitates ambient creep. α′ martensite restrains the nanoindentation creep and hydrogen has little effect on the creep induced by α′ martensite.

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