scholarly journals Relationship of Stiffness-Based Indentation Properties Using Continuous-Stiffness-Measurement Method

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 97 ◽  
Author(s):  
Wai Yeong Huen ◽  
Hyuk Lee ◽  
Vanissorn Vimonsatit ◽  
Priyan Mendis
Keyword(s):  
Elastic Modulus ◽  
Measurement Method ◽  
Computational Simulation ◽  
Accurate Solution ◽  
New Approach ◽  
Stiffness Measurement ◽  
Pile Up ◽  
Continuous Stiffness Measurement ◽  
Relationship Of

The determination of elastic modulus (E) and hardness (H) relies on the accuracy of the contact area under the indenter tip, but this parameter cannot be explicitly measured during the nanoindentation process. This work presents a new approach that can derive the elastic modulus (E) and contact depth (hc) based on measured experiment stiffness using the continuous-stiffness-measurement (CSM) method. To achieve this, an inverse algorithm is proposed by incorporating a set of stiffness-based relationship functions that are derived from combining the dimensional analysis approach and computational simulation. This proposed solution considers both the sink-in and pile-up contact profiles; therefore, it provides a more accurate solution when compared to a conventional method that only considers the sink-in contact profile. While the proposed solution is sensitive to Poisson’s ratio (ν) and the equivalent indentation conical angle (θ), it is not affected by material plasticity, including yield strength (σy) and work hardening (n) for the investigated range of 0.001 < σy/E < 0.5. The proposed stiffness-based approach can be used to consistently derive elastic modulus and hardness by using stiffness and the load-and-unload curve measured by the continuous-stiffness-measurement (CSM) method.

Stiffness Measurement of Permanent Magnet Biased Radial Magnetic Bearing in MSFW

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Sun Jinji ◽  
Bai Guochang ◽  
Yang Lei
Keyword(s):  
Permanent Magnet ◽  
Measurement Method ◽  
Magnetic Circuit ◽  
Magnetic Bearing ◽  
Stiffness Measurement ◽  
Stiffness Characteristics ◽  
Radial Magnetic Bearing ◽  
The Relationship ◽  
Magnetic Center

To measure current stiffness and displacement stiffness of permanent magnet biased radial magnetic bearing, a new stiffness measurement method is proposed for magnetically suspended flywheel (MSFW). The detailed stiffness measurement method is proposed in this paper. At first, the suspension force and stiffness characteristics of the permanent magnet biased radial magnetic bearing are studied using magnetic circuit method and finite element method (FEM). Second, the detailed stiffness measurement method of permanent magnet biased radial magnetic bearing is proposed. It has two procedures, one is the determination of the magnetic center in radial magnetic bearing when the gravity of rotor is in the +x(+y) direction and −x(−y) direction, respectively, then the current stiffness can be obtained, and the other is the calculation of the displacement stiffness according to the relationship between rotor displacement and current. A prototyped MSFW with angular moments of 50 Nms is manufactured, and the proposed stiffness measurement method of permanent magnet biased radial magnetic bearing is verified by prototyped experiments.

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.

Displacements induced by different nanoprecipitates: a SAXS and WAXS anomalous study on Cu–Ni–Fe and Cu–Ni–Co single crystals

2005 ◽  
Vol 38 (3) ◽  
pp. 476-487 ◽  
Author(s):  
O. Lyon ◽  
I. Guillon ◽  
C. Servant ◽  
J. P. Simon
Keyword(s):  
Single Crystals ◽  
New Approach ◽  
X Ray Scattering ◽  
Local Contraction ◽  
Composition Variation ◽  
Pile Up ◽  
The Matrix ◽  
Atomic Scattering ◽  
Fe Alloys

Single crystals of different Cu–Ni–Co and Cu–Ni–Fe alloys, forming spheroid or plate-like precipitates during decomposition, have been studied by small-angle (SAXS) and wide-angle X-ray scattering (WAXS). The SAXS patterns gave information on the sizes and the organization of the precipitates, while the scattering near Bragg peaks allowed a determination of the distortions of the lattice created by these precipitates. The variations of the SAXS spectra with the atomic scattering factors of Co (or Fe) and Ni were used to determine the composition variation between matrix and precipitates (i.e. the `chemical' term), while those of the WAXS spectra enabled the determination of the displacements in the matrix and in the precipitates. The precipitates were found to be enriched in respectively Co and Ni, or Fe and Ni, inducing a local contraction of the lattice, while the matrix (mainly Cu) was of course depleted in the same elements, and its lattice was dilated. These precipitates are piled up along one of the three 〈100〉 `soft' directions. The variations of the deformation field with the precipitate sizes (along both directions parallel and orthogonal to the pile-up orientation), and with the distance between precipitates have been determined. From the knowledge of such variations, it was possible to modify the respective deformation fields in such a way that the respective precipitates have the same sizes, but with a different geometry, and then to isolate what was induced solely by the geometry of a precipitate. Moreover, these experiments yielded the determination of the secondary components of the displacement field (displacements orthogonal to the pile-up direction), which were found to be weak compared with the primary one (parallel to the same direction). Finally, from the variation of the aspect ratio of the precipitates with the aging duration, it was possible to estimate the surface energy of the precipitates, and a comparison between SAXS and WAXS results shows the applicability of this new approach to the decomposition process.

Research on Mechanical Characteristic of Micro-Nano Structure TaC Ceramic by Nanoindentation

2015 ◽  
Vol 1120-1121 ◽  
pp. 11-15 ◽  
Author(s):  
Tian Tian Shao ◽  
Xiao Long Cai ◽  
Jie Fang Wang ◽  
Li Sheng Zhong ◽  
Na Na Zhao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Elastic Modulus ◽  
Creep Property ◽  
High Hardness ◽  
Tantalum Carbide ◽  
Displacement Curve ◽  
Nano Structure ◽  
Pile Up ◽  
Grey Cast ◽  
Continuous Stiffness Measurement

Micro-nanostructure tantalum carbide (TaC) ceramic was prepared on grey cast iron matrix by the combined process of casting and heat treatment. The theoretical foundation of the nanoindentation technique was introduced in detail, and hardness/modular–displacement curve was received from continuous stiffness measurement (CSM). The results show that, elastic modulus (E) and hardness (H) variation with impression depth depend on size effect and matrix effect. There is no impression pile up effecting on hardness value. It was iron (Fe) existing in micro-nanostructure TaC ceramic during heat treatment , which is the main reason of improving creep property of the TaC ceramic. Study on micro-nanostructure TaC ceramic with high hardness, high elastic modulus and good creep property is meaningful to the application in the area of engineering.

Hardness and Elastic Modulus Measurements of AIN and TiN Sub-Micron Thin Films Using the Continuous Stiffness Measurement Technique with Fem Analysis

1999 ◽  
Vol 594 ◽  
Author(s):  
T. A. Rawdanowicz ◽  
J. Sankar ◽  
J. Narayan ◽  
V. Godbole
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Pulsed Laser ◽  
Fem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stiffness Measurement ◽  
Tin Thin Films ◽  
Continuous Stiffness Measurement

AbstractThe hardnesses and elastic moduli of aluminum nitride (AIN) and titanium nitride (TiN) sub-micron thin films pulsed laser deposited (PLD) on silicon (111) were measured using nanoindentation based on a continuous stiffness measurement (CSM) technique. Thin film thicknesses, based on profile measurements of simultaneously grown step samples, are 210 nm and 180 nm with surface roughnesses of 12 nm and 2 nm for AlN and TiN, respectively. X-ray diffraction showed AlN as a highly textured polycrystalline AlN wurzite structure with a (0001) orientation and TiN as a cubic structure with a (111) orientation. The CSM technique provided hardness and elastic modulus as a function of depth. Finite element modeling (FEM) aided in determining the optimum indenter contact depth at which the thin films behaved as a semi-infinite solid with negligible substrate induced artifacts. Hardnesses of these AlN and TiN thin films were, determined analytically, 25 GPa and 33 GPa, as compared to FEM results of 24 GPa and 30 GPa, respectively. The elastic moduli measured 320 GPa and 370 GPa for these AlN and TiN thin films, respectively.

Characterization of Surface Layer of Silicon Wafer by Using Nano Indenter

2007 ◽  
Author(s):  
Yu-Li Sun ◽  
Dun-Wen Zuo ◽  
Yong-Wei Zhu ◽  
Feng Xu ◽  
Min Wang
Keyword(s):  
Elastic Modulus ◽  
Silicon Wafer ◽  
Bulk Material ◽  
Contact Stiffness ◽  
Indentation Test ◽  
Oxide Coating ◽  
Stiffness Measurement ◽  
Contact Depth ◽  
Continuous Stiffness Measurement

Mechanical properties of the silicon wafer are evaluated by a nano indenter system with the continuous stiffness measurement (CSM) technique. Contact stiffness, hardness and elastic modulus of the silicon wafer are continuously measured during the loading in an indentation test. The results show that when the contact depth is between 20 and 32 nm, its contact stiffness is linear with the contact depth, and its hardness and elastic modulus keep constant at 10.2 GPa and 140.3 GPa respectively, which belong to the oxide coating of the silicon wafer. When the contact depth is between 32 and 60 nm, its contact stiffness is not linear with the contact depth, and the hardness and elastic modulus increase rapidly with the contact depth, because they are affected by the bulk material. When the contact depth is over 60 nm, the contact stiffness of the silicon wafer is linear with the contact depth again, and the hardness and elastic modulus keep constant at 12.5 GPa and 165.6 GPa respectively, which belong to the silicon wafer, the bulk material.

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