1. Introduction

Fracture toughness properties yield very essential information on the material behavior with the presence of the sharp crack. This information is in many cases crucial for design or decision about the further use or discarding the component from service. However in many such important cases, there is shortage of the experimental material, and thus assessment has to be done based on miniaturized specimen testing. Examples of the cases when shortage of the

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

experimental material is only available can be residual service life assessment of in-service components, when the experimental material only by semi-destructive approach can be obtained. Cases during development of new materials, generally preparation of the materials with limited volume such as severe plastic deformation processes for bulk nanomaterials preparation. Recently, also for the assessment of the parts produced by additive manufacturing techniques are application for small-size specimen testing.

This chapter is going to provide overview of reporting values of the results obtained with the use of miniaturized specimens with hints how can be small-size-based results related to the standard-sized specimen results. These techniques enable assessment of the fracture behavior from small material volumes allowing, for example, also local anisotropy assessment. In the first part of the chapter, some theoretical background for small-size specimen testing is provided for different fracture regime behaviors ranging from brittle up to full ductile behavior. Several mini specimens' geometries are demonstrated here that are subsequently applied on the experimental materials. Three materials are presented here, ferritic steel used for Master Curve-based assessment and then stainless steel and Ti-alloy produced by additive manufacturing technology. The results are summarized in order to provide inside into the facture behavior assessment with the use of miniaturized specimens providing background for practical application of these approaches.
