Development of High Temperature Nanoindentation Methodology and its Application in the Nanoindentation of Polycrystalline Tungsten in Vacuum to 950 °C

Harris, Adrian; Beake, Ben D.; Armstrong, David E.J.; Davies, M. I.

doi:10.1007/s11340-016-0209-3

Cited by 33 publications

(18 citation statements)

References 56 publications

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“…[35,36] In nanoindentation, the related nanomechanical method based on the same equipment, publications are currently rising every year with respect to the development of high-temperature capability and the limit is being pushed toward 1000°C, reaching application temperatures of turbine materials. [37,38] In addition, variable rate experiments [39] now allow the characterization of rate dependence from the impact [40] to the creep regime [41,42] at any given temperature. These experiments now allow the study of temperaturedependent effects in dislocation plasticity, such as the change in the resistance of the lattice to dislocation motion or transitions in dislocation structure.…”

Section: Investigating Plasticity In Hard Crystalsmentioning

confidence: 99%

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Korte‐Kerzel

2017

MRS Communications

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Recent years have seen an increased application of small-scale uniaxial testing-microcompression-to the study of plasticity in macroscopically brittle materials. By suppressing fast fracture, new insights into deformation mechanisms of more complex crystals have become available, which had previously been out of reach of experiments. Structurally complex intermetallics, metallic compounds, or oxides are commonly brittle, but in some cases extraordinary, though currently mostly unpredictable, mechanical properties are found. This paper aims to give a survey of current advances, outstanding challenges, and practical considerations in testing such hard, brittle, and anisotropic crystals.While the origin of mechanical strength, toughness, and creep resistance is well studied in most metals, much less is known about the properties of more complex crystal structuresdespite their wide use as reinforcement phases and the undiscovered potential in their sheer number and variability. A major challenge in plasticity research of the next years will therefore be to close this gap in knowledge. Small-scale testing techniques have been demonstrated as a key enabling technique for such studies. Most prominent is microcompression, which helps overcome the fundamental challenge of studying plasticity in materials, which suffer from extreme brittleness in conventional testing. [1,2] Their plastic properties may, at first glance, appear to be of only academic interest: aiming to deduce fundamental relationships of crystal plasticity and structure to enable knowledge-guided search and data mining for new structural materials. However, they are in fact essential to performance at the microstructural scale of many advanced and highly alloyed materials and to understanding the effects of alloying strategies aimed at inducing deformability as baseline or reference information. Investigating plasticity in hard crystalsA deep understanding of plasticity and dislocation motion exists in most metallic crystals and strategies to engineer different aspects, for example by adjustment of the stacking fault energy, have been very successful. [3,4] These are being applied-with great effect-to hexagonal metals [3] which in spite of their closely related atomic packing show strongly anisotropic deformation and are therefore much more difficult to deform at low temperatures. In BCC metals, fundamental aspects of dislocation core structure, stress tensor dependence, and resulting non-Schmid behavior, are also still under investigation. [5,6] However, in all of these materials, the availability of large-grained or single crystals with sufficient purity has scarcely been a problem, nor has the ability to deform such samples under carefully controlled conditions. Suitable investigations by conventional, analytical and high-resolution microscopy techniques have also been carried out whenever new methods have allowed researchers to dive deeper into the physics of their plastic deformation.In intermetallics, ceramics, and compounds we face challeng...

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Section: Investigating Plasticity In Hard Crystalsmentioning

confidence: 99%

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Korte‐Kerzel

2017

MRS Communications

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“…1 rather than the elastic modulus since the shape of the indentation curve is subtly influenced by the stiffness of the indenter, so that lower plasticity indices and greater elastic recovery are observed with lower modulus cBN and sapphire indenters than with diamond [8]. H 3 /E 2 is a measure of the resistance to plastic deformation.…”

Section: Introductionmentioning

confidence: 99%

Nano-scratch testing of (Ti,Fe)N x thin films on silicon

Beake

Vishnyakov

Harris

2017

Surface and Coatings Technology

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Thin films of (Ti,Fe)Nx have been produced on silicon wafers with a wide range of compositions and mechanical properties to investigate correlations between the mechanical properties measured by indentation and crack resistance in the highly loaded sliding contact in a nano-scratch test. The nano-scratch test data on the thin films using a well-worn Berkovich indenter with ~1 m end radius were supported by high resolution scanning electron microscopic (SEM) imaging and analytical stress modelling. The results show that mechanical properties of the coating, its thickness and the substrate properties all influence the deformation process. They affect the critical loads required, the type of failures observed and their location relative to the moving probe. The differences in coating mechanical properties affect how the interface is weakened (i.e. by initial substrate or coating yielding or both) and determine the deformation failure mechanism. The load dependence of the friction coefficient provides details of the sliding contact zone and the location of failure relative to the sliding probe. Improved performance was achieved at intermediate hardness and H 3 /E 2 in the nano-scratch tests on thin films. The friction and modelling results strongly suggest that failure at low load on the hardest coatings is due to a combination of high tensile stress at the 2 rear of the contact zone and substrate yield. Designing thin films for protective coatings with in-built dissipative structures (such as soft and low elastic modulus inclusions) and mechanisms to combat stress may be a more successful route to optimise their toughness in highly loaded sliding conditions than aiming to minimise plasticity by increasing their hardness.

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“…For the sake of simplicity, the effect of pile-ups and sink-ins is not taken into account in the calculation of elastic modulus and hardness in the conventional approach. According to previous studies, 11,18) if the thermal drift is measured to be low, it has a negligible effect on elastic modulus and hardness values which are obtained from nano-indentation measurements performed within seconds. Consequently, in the present approach, the measured elastic modulus and hardness values can be used without any additional correction.…”

Section: Geometry Effect Of Indenter Tipmentioning

confidence: 99%

Nano-Indentation Measurement for Heat Resistant Alloys at Elevated Temperatures in Inert Atmosphere

et al. 2019

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A new approach of nano-indentation measurements at elevated temperatures has been developed to evaluate a temperature-dependent mechanical behavior of heat resistant alloys on a submicron scale, where the measurement is conducted in an inert atmosphere to prevent the surface oxidation of a sample and heat an indenter passively. The developed approach enables us to perform nano-indentation testing with a diamond indenter in the temperature range of 23³800°C. The developed approach has been applied to gamma single-phase single-crystal of a nickel-based superalloy. Then the degradations of the sample surface and the indenter tip have been discussed in this case.

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Development of High Temperature Nanoindentation Methodology and its Application in the Nanoindentation of Polycrystalline Tungsten in Vacuum to 950 °C

Cited by 33 publications

References 56 publications

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Microcompression of brittle and anisotropic crystals: recent advances and current challenges in studying plasticity in hard materials

Nano-scratch testing of (Ti,Fe)N x thin films on silicon

Nano-Indentation Measurement for Heat Resistant Alloys at Elevated Temperatures in Inert Atmosphere

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