Mechanical Properties And Defective Effects Of Candidate Structural Materials Of Fusion Reactor

316LN austenitic stainless steels (316LN SS) are considered to have good thermal and mechanical properties, and currently serve as the primary structural materials in the first wall and blanket structure of the International Thermonuclear Experimental Reactor (ITER). Thus, it is necessary to study the fundamental mechanical properties and irradiation effect of 316LN SS. A random solid solution model of Fe-Cr-Ni-Mn-Mo-Si alloy is used for describing 316LN SS. Using first-principles approaches; the elastic constants and ideal strength of the alloys were calculated. Such alloy exhibit good ductile behavior according to the theoretical values of Cauchy pressure and ratio of bulk modulus and shear modulus. Within the 256-atom supercell, inclusion of single vacancy defect further enhances the ductility of the alloy, and the existence of interstitial (Fe, H, He) atoms enhances the Young's modulus.Reduced activation ferritic/martensitic steels (RAFM steels) based on the body centered cubic (bcc) Fe-Cr alloys (7-12 wt.% Cr) with some trace elements (W, V, Si, C) are considered as the primary structural materials of future fusion reactor owing to their attractive properties, such as the excellent resistance to swelling and embrittlement under irradiation and good thermal and mechanical properties. Available experimental results indicate that the addition of Cr into steels can significantly influences the mechanical properties and irradiation effect of ferritic/martensitic steels. So, it is necessary to investigate the fundemental mechanical properties of Fe-Cr alloys with different Cr content. Within a random solid solution model, the lattice constants and the elastic constants of ferromagnetic bcc Fe1-xCrx (0≤x≤0.156) alloys were calculated for different compositions. With addition of Cr content, the lattice parameters of Fe-Cr alloys are larger than that of pure Fe solid, and the corresponding Young's modulus and shear modulus rise non-monotonically with increasing Cr content. All alloys (except 9.4 at.% Cr) exhibit less ductile behavior compared with pure bcc Fe. For the Fe1-xCrx (0≤x≤0.156) alloys, the average magnetic moment per atom decrease linearly with increasing Cr concentration.V-(4-5)wt.% Cr-(4-5)wt.% Ti alloys have been identified as a leading candidate material for first-wall and blanket components of future fusion reactor. This is because of their excellent properties, such as low level of long-term activation, superior mechanical properties, decent thermal creep behavior, high thermal conductivity, and good resistance to irradiation-induced swelling and damage. Thus it is necessary to study the fundamental mechanical properties and the irradiation effects of the V-based alloys. Within a random solid solution model, the elastic constants and ideal strength of the V-4Cr-4Ti and the V-5Cr-5Ti alloys were calculated and compared with those of pure V solid. According to the theoretical Cauchy pressure and the ratio of bulk modulus and shear modulus, both alloys exhibit good ductility. Within the 250-atom supercell, inclusion of one vacancy defect or one interstitial H atom will further enhance the ductility of these alloys.