Journal ArticleDOI
Fracture toughness of polycrystalline tungsten alloys
TLDR
In this article, the effect of microstructure on fracture toughness of tungsten and rhenium alloys was investigated by means of 3-point bending, double cantilever beam and compact tension specimens.Abstract:
Tungsten and tungsten alloys show the typical change in fracture behavior from brittle at low temperatures to ductile at high temperatures. In order to improve the understanding of the effect of microstructure the fracture toughness of pure tungsten, potassium doped tungsten, tungsten with 1 wt.% La 2 O 3 and tungsten rhenium alloys were investigated by means of 3-point bending, double cantilever beam and compact tension specimens. All these materials show the expected increase in fracture toughness with increasing temperature. The experiments demonstrate that grain size, texture, chemical composition, grain boundary segregation and dislocation density seem to have a large effect on fracture toughness below the DBTT. These influences can be seen in the fracture behavior and morphology, where two kinds of fracture occur: on the one hand transgranular and on the other hand intergranular fracture. Therefore, techniques like electron backscatter diffraction (EBSD), Auger electron spectroscopy (AES) and X-ray line profile analysis were used to improve the understanding of the parameters influencing fracture toughness.read more
Citations
More filters
Journal ArticleDOI
Development of advanced high heat flux and plasma-facing materials
Ch. Linsmeier,Michael Rieth,Jarir Aktaa,Takumi Chikada,Anna Rebecca Hoffmann,Jan Hoffmann,A. Houben,Hiroaki Kurishita,Xue Zhou Jin,M. Li,Andrey Litnovsky,S. Matsuo,A. von Müller,Vladica Nikolić,T. Palacios,Reinhard Pippan,D. Qu,J. Reiser,Johann Riesch,T. Shikama,Robert Stieglitz,T. Weber,T. Weber,Stefan Wurster,Jeong-Ha You,Zhangjian Zhou +25 more
TL;DR: In this article, the authors describe the requirements and needs for new, advanced materials for the fusion-facing components of a tokamak/or stellarator reactor, including fiber-reinforced and laminated structures, and mechanically alloyed tungsten materials.
Journal ArticleDOI
Methods for improving ductility of tungsten - A review
Chai Ren,Zhigang Zak Fang,Mark Koopman,Brady G. Butler,James D. Paramore,James D. Paramore,Scott Middlemas +6 more
TL;DR: In this paper, a critical review of the methods that have been reported in the literature for improving the ductility of tungsten in order to understand the critical factors that control the ductile (or lack thereof) in Tungsten.
Journal ArticleDOI
Fracture behaviour of tungsten–vanadium and tungsten–tantalum alloys and composites
TL;DR: In this paper, the influence of both microstructure and chemical composition on the fracture behavior of tungsten-tantalum, tengsten-vanadium composites and alloys of varying chemical compositions is investigated.
Journal ArticleDOI
Influence of impurities on the fracture behaviour of tungsten
TL;DR: In this paper, the effect of grain boundary impurities, especially phosphorous and oxygen, on the fracture resistance of the boundaries of tungsten materials was determined by analysing the fracture surfaces.
Journal ArticleDOI
Interpretation of the deep cracking phenomenon of tungsten monoblock targets observed in high-heat-flux fatigue tests at 20 MW/m2
Muyuan Li,Jeong-Ha You +1 more
TL;DR: In this article, a theoretical interpretation of the observed deep cracking feature is presented, where deep cracking is thought to be a consecutive process of crack initiation and crack growth, which is assumed to be caused by plastic fatigue and brittle facture, respectively.
References
More filters
Journal ArticleDOI
Relationships between the J-integral and the crack opening displacement for stationary and extending cracks
TL;DR: In this paper, the relationship between the J-integral and the crack opening displacement δt is obtained by exploiting the dominance of the Hutchinson-Rice-Rosengren singularity in the crack-tip region.
Journal ArticleDOI
Yielding and fracture in tungsten and tungsten-rhenium alloys
TL;DR: In this paper, a study was made of the mechanical properties of vacuum arc-melted tungsten and rhenium-rhenium alloys in the temperature range 77 °-810 °K in order to elucidate the mechanism by which the addition of Rhenium adds lower the ductile-brittle transition temperature of Tungsten.
Journal ArticleDOI
Brittle fracture and the brittle-to-ductile transition of tungsten
TL;DR: In this article, the authors reviewed the experimental observations and theoretical understanding of the fracture behavior of tungsten in the brittle and semi-brittle regime and showed that dislocation nucleation is the limiting factor at low temperatures, while the dependence on loading rate at intermediate temperatures requires that dislocations mobility takes control.
Journal ArticleDOI
Cleavage anisotropy in tungsten single crystals.
TL;DR: In this paper, an extensive study of the cleavage fracture of tungsten single crystals between 77 K and room temperature was performed, and the dependence of the fracture toughness on temperature and on crack propagation direction as well as the river line patterns on the fracture surfaces clearly indicate that the intrinsic brittle fracture process is anisotropic with respect to the plane and also to the direction of crack propagation.