'Valley' on Load-Penetration Curve Induced by Twinning of α-Ti Polycrystal in Spherical Indentation

2022 ◽  
Author(s):  
Zhankun Sun ◽  
Xinbo Li ◽  
Fuguo Li
Keyword(s):  
Spherical Indentation ◽  
Penetration Curve

Mechanical Responses of Primary-α Ti Grains in Polycrystalline Samples: Part I – Measurements of Spherical Indentation Stress-Strain Curves

2020 ◽  
Author(s):  
Natalia Millan-Espitia ◽  
Soumya Mohan ◽  
Adam Pilchak ◽  
Surya R. Kalidindi
Keyword(s):  
Spherical Indentation ◽  
Stress Strain ◽  
Mechanical Responses

Evaluation of the influence of B and Nb microalloying on the microstructure and strength of 18% Ni maraging steels (C350) using hardness, spherical indentation and tensile tests

2021 ◽  
pp. 117071
Author(s):  
Sepideh Parvinian ◽  
Daniel E. Sievers ◽  
Hamid Garmestani ◽  
Surya R. Kalidindi
Keyword(s):  
Tensile Tests ◽  
Spherical Indentation ◽  
Maraging Steels ◽  
Nb Microalloying

Finite Thickness Influence on Spherical and Conical Indentation on Viscoelastic Thin Polymer Film

2005 ◽  
Vol 127 (1) ◽  
pp. 33-37 ◽  
Author(s):  
V. Gonda ◽  
J. den Toonder ◽  
J. Beijer ◽  
G. Q. Zhang ◽  
L. J. Ernst
Keyword(s):  
Polymer Film ◽  
Material Properties ◽  
Finite Thickness ◽  
Thin Polymer Film ◽  
Spherical Indentation ◽  
Infinite Plane ◽  
Precise Knowledge ◽  
Thin Polymer ◽  
Measurement Results ◽  
Conical Indentation

The thermo-mechanical integration of polymer films requires a precise knowledge of material properties. Nanoindentation is a widely used testing method for the determination of material properties of thin films such as Young’s modulus and the hardness. An important assumption in the analysis of the indentation is that the indented medium is a semi-infinite plane or half space, i.e., it has an “infinite thickness.” In nanoindentation the analyzed material is often a thin film that is deposited on a substrate. If the modulus ratio is small, (soft film on hard substrate) and the penetration depth is small too, then the Hertzian assumption does not hold. We investigate this situation with spherical and conical indentation. Measurement results are shown using spherical indentation on a visco-elastic thin polymer film and a full visco-elastic characterization is presented.

Numerical Predictions of Heat Transfer and Flow Structure in a Square Cross-Section Channel with Various Non-Spherical Indentation Dimples

2013 ◽  
Vol 64 (3) ◽  
pp. 187-215 ◽  
Author(s):  
Gongnan Xie ◽  
Jian Liu ◽  
Philip M. Ligrani ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Flow Structure ◽  
Cross Section ◽  
Spherical Indentation ◽  
Numerical Predictions

Can indentation technique measure unique elastoplastic properties?

2009 ◽  
Vol 24 (3) ◽  
pp. 784-800 ◽  
Author(s):  
Ling Liu ◽  
Nagahisa Ogasawara ◽  
Norimasa Chiba ◽  
Xi Chen
Keyword(s):  
Critical Strain ◽  
Indentation Test ◽  
Strain Curve ◽  
Spherical Indentation ◽  
Plastic Behavior ◽  
Displacement Curve ◽  
Application Range ◽  
Indentation Technique ◽  
Elastoplastic Properties ◽  
Force Displacement

Indentation is widely used to extract material elastoplastic properties from measured force-displacement curves. Many previous studies argued or implied that such a measurement is unique and the whole material stress-strain curve can be measured. Here we show that first, for a given indenter geometry, the indentation test cannot effectively probe material plastic behavior beyond a critical strain, and thus the solution of the reverse analysis of the indentation force-displacement curve is nonunique beyond such a critical strain. Secondly, even within the critical strain, pairs of mystical materials can exist that have essentially identical indentation responses (with differences below the resolution of published indentation techniques) even when the indenter angle is varied over a large range. Thus, fundamental elastoplastic behaviors, such as the yield stress and work hardening properties (functions), cannot be uniquely determined from the force-displacement curves of indentation analyses (including both plural sharp indentation and deep spherical indentation). Explicit algorithms of deriving the mystical materials are established, and we qualitatively correlate the sharp and spherical indentation analyses through the use of critical strain. The theoretical study in this paper addresses important questions of the application range, limitations, and uniqueness of the indentation test, as well as providing useful guidelines to properly use the indentation technique to measure material constitutive properties.

Identification of Hardening Parameters of Metals From Spherical Indentation Tests

2001 ◽  
Vol 123 (3) ◽  
pp. 245-250 ◽  
Author(s):  
S. Kucharski ◽  
Z. Mro´z
Keyword(s):  
Indentation Test ◽  
Strain Curve ◽  
Load Level ◽  
Spherical Indentation ◽  
Indentation Tests ◽  
Geometric Sequence ◽  
Loading And Unloading ◽  
Plastic Hardening ◽  
Hardening Curve ◽  
Two Parameters

The identification method of hardening parameters specifying stress-strain curve is proposed by applying spherical indentation test and measuring the penetration depth during loading and unloading. The loading program is composed of a geometric sequence of loading and partial unloading steps from which the variation of permanent penetration with load level is determined. This data is used for specification of two parameters k and m occurring in the plastic hardening curve εp=σ/k1/m, where εp denotes the plastic strain.

Spherical indentation of closed-cell aluminum foams: An empirical force–depth relation

2014 ◽  
Vol 618 ◽  
pp. 433-437 ◽  
Author(s):  
Zhibin Li ◽  
Zhijun Zheng ◽  
Jilin Yu ◽  
Jie Yang ◽  
Fangyun Lu
Keyword(s):  
Spherical Indentation ◽  
Aluminum Foams ◽  
Closed Cell
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