Book contents
- Frontmatter
- Contents
- Preface
- 1 General introduction
- 2 Basic composite mechanics
- 3 The Eshelby approach to modelling composites
- 4 Plastic deformation
- 5 Thermal effects and high temperature behaviour
- 6 The interfacial region
- 7 Fracture processes and failure mechanisms
- 8 Transport properties and environmental performance
- 9 Fabrication processes
- 10 Development of matrix microstructure
- 11 Testing and characterisation techniques
- 12 Applications
- Appendix I Nomenclature
- Appendix II Matrices and reinforcements – selected thermophysical properties
- Appendix III The basic Eshelby S tensors
- Appendix IV Listing of a program for an Eshelby calculation
- Author index
- Subject index
11 - Testing and characterisation techniques
Published online by Cambridge University Press: 04 February 2010
- Frontmatter
- Contents
- Preface
- 1 General introduction
- 2 Basic composite mechanics
- 3 The Eshelby approach to modelling composites
- 4 Plastic deformation
- 5 Thermal effects and high temperature behaviour
- 6 The interfacial region
- 7 Fracture processes and failure mechanisms
- 8 Transport properties and environmental performance
- 9 Fabrication processes
- 10 Development of matrix microstructure
- 11 Testing and characterisation techniques
- 12 Applications
- Appendix I Nomenclature
- Appendix II Matrices and reinforcements – selected thermophysical properties
- Appendix III The basic Eshelby S tensors
- Appendix IV Listing of a program for an Eshelby calculation
- Author index
- Subject index
Summary
Progress in our understanding of metal matrix composites is heavily reliant on the range of available experimental techniques and the correct selection by the researcher of the most appropriate method for a specific task. In this chapter an outline is given of some of the main testing and characterisation techniques which have been used for composite evaluation, looking first at the basic principles and capability of each technique, before going on to discuss application to MMCs. Each section also contains a source of references which provide the necessary technical details.
Measurement of Young's modulus
Basic principle and capability
The aim is to characterise the relationship between an applied load and a material's elastic (reversible) variation in strain. The available experimental approaches can be split into two broad classes; mechanical or static methods, and ultrasonic or dynamic methods. Their measurement capability in terms of accuracy is similar (±0.5 GPa).
Of all the different means of characterising stiffness, the following measures are perhaps the most popular.
(1) the tangent to the initial stress-strain slope
(2) the tangent, subsequent to prestraining, of the initial slope on reloading
(3) the tangent, subsequent to prestraining, of the initial slope of the unloading curve
(4) the tangent to the reloading curve, subsequent to prestraining and low stress amplitude cycling about zero until stress/strain hysteresis is negligible
(5) the speed of ultrasonic waves through the medium
(6) the frequency of resonant standing vibrations, which are related to the dimensions of the specimen as well as to the stiffness of the material.
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- Information
- An Introduction to Metal Matrix Composites , pp. 399 - 453Publisher: Cambridge University PressPrint publication year: 1993
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