Mechanical properties of as-fabricated and 2300 °C annealed tungsten wire tested up to 600 °C. (August 2017)

• Record Type: Journal Article
• Authors: Terentyev, D.; Riesch, J.; Lebediev, S.; Bakaeva, A.; Coenen, J.W.
• Is Part Of: International journal of refractory metals & hard materials. Volume 66(2017)
• Page Start: 127
• Page End: 134
• Publication Date: 2017-08
• Subjects: Tungsten -- Fiber -- Plasticity -- Potassium doped; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2017.03.011
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: Recent efforts dedicated to the mitigation of tungsten brittleness have demonstrated that tungsten fiber-reinforced composites acquire pseudo ductility even at room temperature. Crack extension and fracture process is basically defined by the strength of tungsten fibers. Here, we move forward and report the results of mechanical and microstructural investigation of different grades of W wire with a diameter of 150 μm at elevated temperature up to 600 °C. The results demonstrated that potassium doping to the wire in the as-fabricated state does not principally change the mechanical response, and the fracture occurs by grain elongation and delamination. Both fracture stress and fracture strain decrease with increasing test temperature. Contrary to the as-fabricated wire, the potassium-doped wire annealed at 2300 °C exhibits much lower fracture stress. The fracture mechanism also differs, namely: cleavage below 300 °C and ductile necking above. The change in the fracture mechanism is accompanied with a significant increase of the elongation to fracture being ~ 5% around 300 °C. Highlights: High temperature annealed tungsten wire is tested. Recrystallization of tungsten wire leads to severe embrittlement. Recrystallization of wire alternates mechanism of plastic deformation.