A Load-Based Multiple-Partial Unloading Micro-Indentation Technique for Mechanical Property Evaluation

Feng, C.R.; Tannenbaum, J. M.; Kang, Bruce S.; Alvin, Mary Anne

doi:10.1007/s11340-009-9271-4

Cited by 20 publications

(18 citation statements)

References 14 publications

(21 reference statements)

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“…The indentation technique was initially applied to determine the hardness and Young's modulus of timeindependent elastic materials [5][6][7][8], and it has been used more recently to characterize viscoelastic behavior of polymers and other time-dependent materials [9][10][11][12][13][14][15][16][17]. Lee and Radok [18] obtained expressions for the load and penetration during the spherical indentation of a linear viscoelastic material by replacing the elastic modulus in the classical Hertz solution [19] with a hereditary integral.…”

Section: Introductionmentioning

confidence: 99%

Determination of Asphalt Binder Creep Compliance Using Depth-Sensing Indentation

Zofka

Nener-Plante

2011

Exp Mech

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Asphalt binders are common construction materials, however due to time-and temperature-dependence, their mechanical properties are often difficult to characterize. Several standard tests methods exist to describe their complex behavior. This paper presents an exploratory feasibility study of a flat-tip indentation testing to analyze the linear viscoelastic properties of asphalt binders. Depthsensing indentation testing has been extensively used to characterize the properties of many engineering materials, however the applications to asphalt binders are very limited. This paper presents a simple solution for the creep compliance in tension derived for flat-tipped indenter. This solution was verified with the Finite Element Analysis and then applied to the experimental results from the indentation testing performed on one typical unmodified asphalt binder. The testing was conducted at three different low temperatures and under three different creep load levels to verity the linearity of the response, and to evaluate the robustness and applicability of the indentation method. Furthermore, the creep compliance functions determined from the indentation testing were compared with a more traditional 3-point bending experiments. The results show that there is a non-uniform discrepancy between the two testing methods, most likely due to nonlinear behavior of the asphalt binder at higher temperatures and micro-damage of the binder samples at lower temperatures. Other possible sources of error between indentation and 3-point bending are problems determining the initial tip-specimen contact surface and possible tip-specimen adhesion. It is concluded that flat-tipped indentation at low temperatures should be performed at lower load levels to avoid excessive stress concentrations that leads to micro-damage and nonlinear response of asphalt binders. Alternatively, asphalt binders at low temperatures could be evaluated using different indenter geometries, such as spherical or pyramidal, using corresponding parameter interpretation procedures.

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Section: Introductionmentioning

confidence: 99%

Determination of Asphalt Binder Creep Compliance Using Depth-Sensing Indentation

Zofka

Nener-Plante

2011

Exp Mech

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“…A method to obtain the elastic modulus, from those hardness indentator experiments, is based on classical Hertz contact mechanics and was proposed by Sneddon [8]. This technique is applied widely in material and biomechanical sciences, at microscale [4,9,10,11,12,13,14,15] and nanoscale [16,17,18,19]. Such tests use different punches (cylindrical, conical, Berkovich, Vickers) and different loading protocols [11,15,20].…”

Section: Introductionmentioning

confidence: 99%

New Double Indentation Technique for Measurement of the Elasticity Modulus of Thin Objects

2010

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In this paper we introduce a new method to determine the Young's modulus of thin (biological) samples. The method is especially suitable for small objects with a thickness of a few hundred micrometers. Such specimens cannot be examined with existing tests: compression and tensile tests need well-known geometry and boundary conditions while classic indentation tests need relatively thick pieces of material. In order to determine the elastic modulus we use the indentation theory as proposed by Sneddon and correct it with a finite element calculated κ factor to compensate for the small thickness. In order to avoid material deformations at the contact zone between the sample bottom and the sample stage, we replace the sample stage by a second indentation needle. In this way the sample can be clamped between two identical needles and a virtual mirror plane is introduced. The new method was used on four test-materials and results agreed well with the outcome of a standard compression method applied on large samples of the same materials. As an application example the technique was applied on thin biological samples, namely middle ear ossicles of rabbits.

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“…As a result, an alternative method, developed at West Virginia University, allows for a theoretical solution for the Young's Modulus measurement. Equation A.9 can be rewritten as [49]:…”

Section: A2 Contact Mechanics and Indentationmentioning

confidence: 99%

“…It was shown the slope C can be used to determine the reduced modulus of the system. Thus, if the system compliance can be measured or calibrated during the indentation, evaluation of the indentation to the material does not need evaluation [49].…”

Section: A-3mentioning

confidence: 99%

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Development of Ni-based Oxide Dispersion Strengthened (ODS) powder particles for Metal Additive Manufacturing (AM) Applications

McPherson¹

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The capabilities of Additive Manufacturing (AM) techniques have grown rapidly in recent years, however, current available metal powders for AM processes, such as Powder Bed Fusion and Directed Energy Deposition, are limited and primarily fabricated through gas atomization process which; the gas atomization process is capable of producing metal powders 15 µm to 150 µm in size with near spherical shape. Despite the advantages of atomization process, iron or nickel-based Oxide Dispersion Strengthened (ODS) powders, with nanocrystalline microstructure, cannot be produced with the gas atomization process because of the high melting temperature of yttrium (III) oxide (Y2O3, 2425 °C) compared to iron (Fe, 1538 °C), nickel (Ni, 1668 °C), chromium (Cr, 1907 °C) and aluminum (Al, 660 °C), thus, uniform dispersion of Y2O3 is problematic for ODS powders. In this work, a combination of Mechano-Chemical Bonding (MCB) process and Mechanical Alloying (MA) by planetary ball milling (BM) will be implemented to produce ODS powders suitable for AM applications. The MCB process fractures and uniformly disperse the Y2O3 nanoparticles and the nanoparticles are bonded on the surface of the master particles (Ni and Cr). Also, the MA process, because of the constant fracturing and cold-welding of the elemental particles, produces alloyed ODS powders with suitable uniform size distribution, near spherical shape, and nanocrystalline microstructure. The objectives of this research are to (1) optimize the MCB+BM processing parameters and (2) study effects of the process parameters on the size, morphology, and microstructure of Ni-based ODS powders for metal AM applications using Laser Engineering Net Shaping (LENS) machine. Results showed that Ni-based ODS particles with nearly spherical in morphology, average particle size of 15 μm, uniform dispersion of Y2O3, and nanocrystalline microstructure can be successfully produced via the proposed MCB + BM methodology. These resultant Ni-based ODS particles were successfully used on a LENS AM machine to produce coupon specimen. The coupon specimen microstructure contains γ-NiAl matrix and submicron γ'-Ni3Al strengthening phase.

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A Load-Based Multiple-Partial Unloading Micro-Indentation Technique for Mechanical Property Evaluation

Cited by 20 publications

References 14 publications

Determination of Asphalt Binder Creep Compliance Using Depth-Sensing Indentation

Determination of Asphalt Binder Creep Compliance Using Depth-Sensing Indentation

New Double Indentation Technique for Measurement of the Elasticity Modulus of Thin Objects

Development of Ni-based Oxide Dispersion Strengthened (ODS) powder particles for Metal Additive Manufacturing (AM) Applications

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