Details

Autor(en) / Beteiligte

• Altstadt, E.
• Bergner, F.
• Das, A.
• Houska, M.

Titel

Effect of anisotropic microstructure of ODS steels on small punch test results

Ist Teil von

• Theoretical and applied fracture mechanics, 2019-04, Vol.100, p.191-199

Ort / Verlag

Amsterdam: Elsevier Ltd

Erscheinungsjahr

2019

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• •Small punch test on 3 ODS steels; comparison of hot-rolled vs. hot-extruded ODS.•In-depth analysis of load drops (pop-ins) in the force-displacement curves.•Analogy of secondary cracks (fracture mechanics) and flakes in SP fractures surfaces.•Effect of anisotropy on of the correlation between SP and KLST based DBTTs. Hot rolling and hot extrusion of oxide-dispersion strengthened (ODS) ferritic steels give rise to anisotropic microstructures and mechanical properties and may provoke related phenomena such as secondary cracking. In this study, we consider the small punch (SP) test – a method, applicable in the case of small amounts of available material and well established for isotropic materials. The SP test was applied to investigate the effect of sample orientation on deformation and cracking for one hot-rolled and two hot-extruded ODS ferritic steels. Existing microstructural evidence is used to rationalize the observed anisotropic fracture behaviour. The SP test results are compared with those from existing fracture mechanics tests based on sub-sized C(T) samples. The applicability of the empirical conversion of SP-based into Charpy-based transition temperatures is evaluated. The fractographic manifestation of load drops in SP load-displacement curves is identified and the analogy to secondary cracking in fracture mechanics tests is shown.