TY - JOUR
T1 - EBSD characterization of pure and K-doped tungsten fibers annealed at different temperatures
AU - Tanure, Leandro
AU - Terentyev, Dmitry
AU - Nikolic, Vladica
AU - Riesch, Johan
AU - Verbeken, Kim
N1 - Score=10
PY - 2020/5/8
Y1 - 2020/5/8
N2 - Electron Backscatter Diffraction was used to investigate the grain boundary character and triple junction distributions as well as the microtexture on drawn pure and potassium doped (60e75 ppm) tungsten wires. With an approximate diameter of 150 mm, pureWwires were annealed at 1300, 1600 and 1900 C, whereas K-doped material was annealed at 1300, 1600 and 2100 C. The annealing was performed under hydrogen atmosphere for 30 min. Both longitudinal and transversal sections were analyzed to assess anisotropic features. Up to 1600 C, all conditions presented a strong <110> fiber texture parallel to the drawing axis. With increasing annealing temperature, the pure W material developed a more heterogeneous fiber texture while for the K-doped material, it remained homogeneous. Orientation correlation function (OCF) analysis suggested sub-grain coarsening as the recrystallization mechanism while grain boundary density and grain boundary character distribution exhibited anisotropic behavior, as well as the triple junction distribution network. On the other hand, the coincidence site lattices (CSL) distribution
did not present any anisotropy and followed the empirical law of the inverse cubic root of S-value. For all conditions, the most abundant CSL boundaries were S3, S9, S11, S17b, S19a, S27a and S33a. Based on the statistics of the triple junction types and their resistance to intergranular cracking, it was revealed that increasing the annealing temperature might play a role in crack deflection since the resistance to intergranular crack growth is increased in the transversal section and reduced in the longitudinal section. This anisotropic behavior is preserved up to a higher annealing temperature in the K-doped material.
AB - Electron Backscatter Diffraction was used to investigate the grain boundary character and triple junction distributions as well as the microtexture on drawn pure and potassium doped (60e75 ppm) tungsten wires. With an approximate diameter of 150 mm, pureWwires were annealed at 1300, 1600 and 1900 C, whereas K-doped material was annealed at 1300, 1600 and 2100 C. The annealing was performed under hydrogen atmosphere for 30 min. Both longitudinal and transversal sections were analyzed to assess anisotropic features. Up to 1600 C, all conditions presented a strong <110> fiber texture parallel to the drawing axis. With increasing annealing temperature, the pure W material developed a more heterogeneous fiber texture while for the K-doped material, it remained homogeneous. Orientation correlation function (OCF) analysis suggested sub-grain coarsening as the recrystallization mechanism while grain boundary density and grain boundary character distribution exhibited anisotropic behavior, as well as the triple junction distribution network. On the other hand, the coincidence site lattices (CSL) distribution
did not present any anisotropy and followed the empirical law of the inverse cubic root of S-value. For all conditions, the most abundant CSL boundaries were S3, S9, S11, S17b, S19a, S27a and S33a. Based on the statistics of the triple junction types and their resistance to intergranular cracking, it was revealed that increasing the annealing temperature might play a role in crack deflection since the resistance to intergranular crack growth is increased in the transversal section and reduced in the longitudinal section. This anisotropic behavior is preserved up to a higher annealing temperature in the K-doped material.
KW - ITER
KW - EBSD
KW - Texture
KW - Tungsten fiber
KW - Potassium doped
KW - Grain boundary
KW - Triple junction
KW - Annealing
UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/39035474
U2 - 10.1016/j.jnucmat.2020.152201
DO - 10.1016/j.jnucmat.2020.152201
M3 - Article
SN - 0022-3115
VL - 537
SP - 1
EP - 13
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
M1 - 152201
ER -