Improved fracture behavior and microstructural characterization of thin tungsten foils

Nuclear Materials and Energy

Stefan Wurster¹  Daniel Firneis²  Vladica Nikolic²  Reinhard Pippan² 

[1] Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben, Austria;Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria;

关键词: Thin tungsten foil;    Fracture toughness;    High and low temperature fracture experiments;    LEFM;    EBSD analysis;    SEM analysis;   

DOI  :  10.1016/j.nme.2016.06.003

来源: DOAJ

【 摘 要 】

This study is focused towards the development of the technique for investigating the fracture behaviour of 100µm thick rolled tungsten foils, with a purity of 99.97%. Electron backscatter diffraction (EBSD) scans reveal that the grains are elongated along the rolling direction of the foil, which has a very strong {100}<011> texture. The test specimens were fabricated by electrical discharge machining (EDM) and cracks were initiated by consecutively using a diamond wire saw, a razor blade and a focused ion beam (FIB) workstation. Fracture experiments were performed at temperatures from −196°C to 800°C. The investigation of fracture appearance shows an improved behavior and significantly higher values of conditional fracture toughness Kq compared to bulk W-materials, which can be related to a higher degree of deformation during the production process. A high toughness at room temperature (RT) and 200°C, slowly decreases when approaching the highest testing temperature of 800°C. The most significant result reveals that the ductile to brittle transition temperature (DBTT) is around RT, which is an extraordinary result for any tungsten material. The fracture surfaces, investigated with a scanning electron microscope (SEM), show a transition from cleavage fracture at liquid nitrogen temperature, through pronounced delamination within the foil plane at ambient temperatures to ductile fracture at the highest testing temperatures.

【 授权许可】

Unknown