Recent developments in small punch testing: tensile and fracture testing

Neutron irradiation in nuclear power plants leads to microstructural changes resulting in the degradation of important properties in structural materials. One of the effects of neutron irradiation is a shift of the ductile to brittle transition temperature (DBTT) towards higher temperatures. The need for characterizing in service materials from nuclear power plants as well as irradiation testing of new materials has led to a need for test techniques using only a small amount of material. The small punch test is one of these techniques: a small hemispherical punch is pushed along its axis of symmetry through a small disc shaped specimen. Normally either the punch is pushed at a fixed displacement rate and the force is measured as a function of displacement (tensile test) or the force is kept constant and the displacement is measured as a function of time (creep test). This paper lays out the working principle of the small punch tensile/fracture test. Current approaches for determining yield stress, ultimate tensile strength and DBTT from small punch data are reviewed. Based on data from ongoing research projects some new proposals and the application to fuel claddings are presented. Finally an overview over the currently available international standards is given.

BRUCHHAUSEN Matthias;  HOLMSTROM Bjorn;  SIMONOVSKI Igor;  AUSTIN Timothy;  RIPPLINGER Stefan;  LAPETITE Jean-Marc;  DE HAAN Fredericus; 

2016-04-20

Grupo Español de Fractura

JRC100726

http://www.gef2016.es/en/home,    https://publications.jrc.ec.europa.eu/repository/handle/JRC100726,