The Design,Fabrication And Property Evaluation Of Yttrium-doped Tungsten Alloys For Fusion Reactor Applications

Controlled Fusion energy is the most promising future energy source for solving the energy crisis in the development of the economic and society.The stability and reliability of plasma facing materials(PFMs)is directly to the safe and stable running of the future fusion reactor.Due to the excellent performance,such as high melting point,high thermal conductivity,low sputtering yield,low tritium inventory,et al.W has been chosen as the PFMs for future fusion reactor applications.However,W shows a high ductile to brittle transition temperature,low recrystallization temperature and poor thermal shock loading resistance,which constrain its application.Based on the above mentioned reasons,yttria(Y2O3)dispersion strengthened W alloys were produced by two different fabrication methods,i.e.,high energy ball milling together with spark plasma sintering,and higher energy ball milling together with industrial sintering and rolling.Due to the strong affinity towards oxygen,Yttrium(Y)was used as doping agent instead of Y2O3.Their mechanical properties,thermal conductivity,thermal shock loading resistance and deuterium implantation behavior were evaluated and compared to pure W.The main research results are summarized as follows:(1)While using the fabrication method of high energy ball milling together with industrial sintering and rolling,fine-grained W alloy with a relative density of 99.3%,uniformly distributed Y2O3 dispersions,less detrimental impurities and superior mechanical properties was developed.This alloy shows a room temperature bending strength of 2153 MPa,and an obvious plastic deformation behavior at 470 K;(2)The fabrication method exerts significant influence on the thermal conductivity,mechanical properties,thermal shock loading resistance of Y2O3 dispersion strengthened W alloys.While adding 1 wt.%Y into W,the ability of W materials during thermal shock loading,including plastic deformation resistance,inhibiting the W grain growth and surface roughness growth,is obviously improved;(3)Sample temperature dramatically influences the blistering and deuterium retention behavior of different tungsten materials.The blistering behavior of tungsten materials is remarkably suppressed due to the addition of 1 wt.%Y into W.