Nuclear fusion energy is abundant and safe with a good application prospect, and thus might become the main energy source for human beings.
In a nuclear fusion apparatus, a plasma-facing material surface on the inner wall (hereinafter referred to as a “wall surface”) will be subjected to some ordeals, such as high thermal shock, high doses of neutron irradiation, deuterium and helium plasma irradiation, and the like. Refractory metals such as tungsten, molybdenum, and the like, are commonly used as plasma-facing materials, and tungsten is now a widely accepted and preferred plasma-facing material. However, when tungsten, molybdenum, and the like are irradiated by deuterium or helium plasma for a long period of time, hydrogen, helium, and isotopes thereof will aggregate under their surface layer, leading to a surface-blistering phenomenon. Moreover, during the operation of a nuclear fusion apparatus, there exists a continuous temperature fluctuation, which produces a thermal fatigue effect on the wall surface, i.e., thermal fatigue cracks on the surface. These phenomena may damage the wall surface, affect service conditions of the wall surface material and thus shorten the life of the wall material. Hence, it is an important researching subject in the field of nuclear fusion material to improve the resistance of a wall surface material to the fusion plasma irradiation.
Previously, in order to inhibit surface blistering, some methods were proposed that can achieve this object in question by using a gradient-porous structure or a columnar crystal. However, none of them can effectively reduce thermal fatigue cracking damage and the preparation processes used for these methods are relatively complicated.