Discrete dislocation modelling of Nano- and Micro-indentation

Since a long time, indentation testing is a commonly used technique to measure the properties of materials such as hardness and Young's modulus. Recently, nano-indentation is increasingly employed to investigate the properties of very small volumes of material as encountered in today's miniature technology. While an indentation experiment is performed relatively easily, the interpretation of the outcome is far from being trivial. The minimum requirement is the availability of a theory for the deformation processes taking place during indentation. As far as the plastic deformation of metals is concerned, this is precisely the scientific challenge because plasticity in volumes of cubic micrometers is size dependent. While the origin and description of this size dependence are subject of intense debate, one thing is certain: classical plasticity theories do not apply at length scales of tens of micrometers and below since these theories do not contain a material length scale and are therefore size independent.

In this research, a model is adopted that does have an inherent material length scale and aims at bridging the length scale gap between atomistics and continuum theories: discrete dislocation plasticity. In this theory, plasticity is viewed as originating from the collective motion of dislocations, which are described as line defects in a linear elastic continuum.

Experiments have convincingly demonstrated that indentation at the nano or micro scale also reveal a size effect

	Title and contents
	Chapter 1
	Chapter 2
	Chapter 3
	Chapter 4
	Chapter 5
	Chapter 6
	Chapter 7
	Chapter 8
	Conclusion and recommendations
	Summary
	Acknowledgment

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