Stress Analysis in Tungsten Alloys Modified with Plasma Flows and Irradiated with Helium Ions

Abstract

As the development of nuclear fusion depends on plasma-facing materials, new methods for improving the radiation resistance of tungsten are being created and tested. This paper presents the results of studying the structure, surface morphology, phase composition, and residual internal stresses in tungsten alloys modified by plasma flows and irradiated with helium ions with an energy of 40 keV and doses of (1–3) × 1017 cm−2 . It is shown that the effect of compression plasma flows on tungsten leads to the modification of its grain structure in the near-surface layer, forming dispersed cells of 220–320 nm in size due to high-speed crystallization. The results of measuring the lattice parameters and internal stresses in irradiated tungsten alloys showed that the near-surface layer accumulates radiation defects, creating internal stresses, the relaxation of which leads to local destruction of the surface. Preliminary plasma treatment creates an increased density of intergranular boundaries, which serve as sinks for radiation defects and increase the radiation resistance of tungsten alloys.