Journal ArticleDOI
An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments
Warren C. Oliver,George M. Pharr +1 more
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In this paper, the authors used a Berkovich indenter to determine hardness and elastic modulus from indentation load-displacement data, and showed that the curve of the curve is not linear, even in the initial stages of the unloading process.Abstract:
The indentation load-displacement behavior of six materials tested with a Berkovich indenter has been carefully documented to establish an improved method for determining hardness and elastic modulus from indentation load-displacement data. The materials included fused silica, soda–lime glass, and single crystals of aluminum, tungsten, quartz, and sapphire. It is shown that the load–displacement curves during unloading in these materials are not linear, even in the initial stages, thereby suggesting that the flat punch approximation used so often in the analysis of unloading data is not entirely adequate. An analysis technique is presented that accounts for the curvature in the unloading data and provides a physically justifiable procedure for determining the depth which should be used in conjunction with the indenter shape function to establish the contact area at peak load. The hardnesses and elastic moduli of the six materials are computed using the analysis procedure and compared with values determined by independent means to assess the accuracy of the method. The results show that with good technique, moduli can be measured to within 5%.read more
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Journal ArticleDOI
Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology
Warren C. Oliver,George M. Pharr +1 more
TL;DR: In this article, the authors review the current understanding of the mechanics governing elastic-plastic indentation as they pertain to load and depth-sensing indentation testing of monolithic materials and provide an update of how they now implement the method to make the most accurate mechanical property measurements.
Journal ArticleDOI
Microstructures and properties of high-entropy alloys
TL;DR: The concept of high entropy introduces a new path of developing advanced materials with unique properties, which cannot be achieved by the conventional micro-alloying approach based on only one dominant element as mentioned in this paper.
Journal ArticleDOI
Force measurements with the atomic force microscope: Technique, interpretation and applications
TL;DR: The atomic force microscope (AFM) is not only used to image the topography of solid surfaces at high resolution but also to measure force-versus-distance curves as discussed by the authors, which provide valuable information on local material properties such as elasticity, hardness, Hamaker constant, adhesion and surface charge densities.
Journal ArticleDOI
Dislocation nucleation and defect structure during surface indentation
TL;DR: In this paper, an atomistic imaging of dislocation nucleation during displacement controlled indentation on a passivated surface is presented, where defects are located and imaged by local deviations from centrosymmetry.
Book
Thin Film Materials: Stress, Defect Formation and Surface Evolution
L. B. Freund,Subra Suresh +1 more
TL;DR: The role of stress in mass transport is discussed in this article, where the authors consider anisotropic and patterned films, buckling, bulging, peeling and fracture.
References
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Book
Theory of Dislocations
John Price Hirth,Jens Lothe +1 more
TL;DR: Dislocations in Isotropic Continua: Effects of Crystal Structure on Dislocations and Dislocation-Point-Defect Interactions at Finite temperatures.
Journal ArticleDOI
A Critical Evaluation of Indentation Techniques for Measuring Fracture Toughness: I, Direct Crack Measurements
TL;DR: In this paper, the application of indentation techniques to the evaluation of fracture toughness is examined critically, in two parts: the first part is focused on an approach which involves direct measurement of Vickers-produced radial cracks as a function of the indentation load.
A Critical evaluation of indentation techniques for measuring fracture toughness
TL;DR: In this paper, the application of indentation techniques to the evaluation of fracture toughness is examined critically, in two parts: the first part is focused on an approach which involves direct measurement of Vickers-produced radial cracks as a function of the indentation load.
Journal ArticleDOI
The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile
TL;DR: In this article, a solution of the axisymmetric Boussinesq problem is derived from which are deduced simple formulae for the depth of penetration of the tip of a punch of arbitrary profile and for the total load which must be applied to the punch to achieve this penetration.
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