Plastic deformation of recrystallized tungsten-potassium wires: Constitutive deformation law in the temperature range 22–600 °C. (June 2018)

• Record Type: Journal Article
• Authors: Terentyev, D.; Riesch, J.; Lebediev, S.; Khvan, T.; Zinovev, A.; Rasiński, M.; Dubinko, A.; Coenen, J.W.
• Is Part Of: International journal of refractory metals & hard materials. Volume 73(2018)
• Page Start: 38
• Page End: 45
• Publication Date: 2018-06
• Subjects: Tungsten -- Tungsten wire -- 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.2018.01.012
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: Recent efforts dedicated to the mitigation of tungsten (W) brittleness have demonstrated that tungsten fiber-reinforced composites acquire extrinsic toughening even at room temperature, which is due to the outstanding strength of W wires. However, high temperature operation/fabrication of the fiber-reinforced composite might result in the degradation of the mechanical properties of W wires. To address this, we investigate mechanical and microstructural properties of potassium-doped tungsten wires, being heat treated at 2300 °C and tested in temperature range 22–600 °C. Based on the microscopic analysis, the engineering deformation curves are converted into actual stress - strain dataset, accounting for the local necking. The analysis demonstrates that local strain in the necking region can reach up to 50% and the total elongation monotonically increases with temperature, while the ultimate tensile strength goes down. Preliminary transmission electron microscopy analysis using FIB-cut lamella from the necking region revealed the presence of curved dislocation lines in the sample tested at 300 °C, proving that plastic deformation occurred by dislocation glide. Highlights: High temperature annealed tungsten wire is tested. Recrystallization of tungsten wire leads to severe embrittlement. Recrystallization of wire alternates mechanism of plastic deformation.