Behaviors of full compositional W/Cu functionally gradient materials exposed to the edge plasma of HT-7 tokamak

• Published in: Journal of nuclear materials 2013-04, Vol.435 (1-3), p.107-111
• Main Authors: Zhu, D.H., Chen, J.L., Zhou, Z.J., Yan, R., Ding, R.
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Copper; Cracks; Density; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Exposure; Fatigue failure; Fission nuclear power plants; Fuels; Functionally gradient materials; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Stress concentration; Tokamak devices
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2012.12.044

To investigate the behaviors of graded structure materials under plasma loading, six-layered W/Cu functionally gradient materials (FGMs) with full compositional distributions (from 0% to 100%) were successfully fabricated by resistance sintering under ultra-high pressure (RSUHP) method and were exposed to the edge plasma of the HT-7 tokamak. After about 210 shots plasma loading with an estimated power density in the range of 2–7MW/m2, there is no detaching found at the graded interface corners where the thermal stress concentration is expected and the fatigue failures often occur initially, however, the brittle W layer develops the macroscopic cracks which can extend deeply into the interface and results in the interface failure or even the exfoliated W layer. To avoid these destructions for W/Cu FGMs during wall application, it is necessary to ameliorate the W layer by optimizing the initial powders and sintering parameters.