Abstract
We have studied the microstructure of tungsten fibers, which are considered as reinforcement elements for the
advanced tungsten composites (Wf/W) known to exhibit pseudo ductile behaviour at room temperature. The
potentially negative impact of the high temperature annealing, expected under operation in fusion environment,
remains to be explored and mitigated. Doping by potassium is considered as a main option to delay recrystallization
and grain growth inside the drawn tungsten wires to a higher temperature. Here, we have performed
a systematic analysis of the fracture surface of pure and K-doped tungsten wires which were annealed
prior to a uniaxial tensile test. The results demonstrate that the fracture mechanism depends strongly on the
annealing temperature and presence of potassium doping. Four fracture mechanisms were clearly distinguished
and classified by converting into deformation maps as a function of annealing and test temperature. By summarizing
all previously available results and current ones, one can demonstrate that potassium doping delays
massive grain growth (and subsequent loss of strength) by ∼600 °C as compared to the pure W wire and this
positive effect holds for the deformation not only at room temperature but at least up to 500 °C.
Original language | English |
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Pages (from-to) | 1-4 |
Number of pages | 4 |
Journal | fusion engineering and design |
DOIs | |
State | Published - 10 Feb 2019 |
Event | 2018 - SOFT: 30th edition of the Symposium on Fusion Technology - Giardini Naxos, Messina, Sicily Duration: 16 Sep 2018 → 21 Sep 2018 |