Neutron Irradiation Effect on Isotopically Tailored 11B4C

Thermal conductivity of boron carbide under fast neutron irradiation

“…Maruyama et al [3] demonstrated that the thermal conductivity of boron carbide decreases rapidly to 1/3 of the unirradiated value as early as the burnup of ~5×10 26 cap/m 3 , and then further decreases gradually to 1/10 at about 35×10 26 cap/m 3 . Some other neutron irradiation investigations have also verified the abrupt degradation of thermal conductivity of boron carbide at the very beginning of the irradiation process [5][6][7].…”

“…Fortunately, the post-irradiation annealing may provide an effective way to separate out the contribution of Frenkel defect pairs from that of the substitutional defects on thermal conductivity. The almost complete recovery of the thermal conductivity of the irradiated 11 B 4 C sample [6] implies that Frenkel defect pairs due to the collisions with neutrons can be annihilated by high temperature annealing. In contrast, the substitutional defects of boron atoms by locally generated lithium atoms cannot be eliminated, and are believed to be retained in the lattice.…”

“…These two types of point defects affect the thermal conductivity simultaneously from the start. Morohashi et al [6] carried out an annealing measurement of thermal conductivities of the irradiated 11 B 4 C sample, the neutron captures cannot take place during the irradiation. Frenkel defect pairs due to the elastic collisions with neutrons are believed to be the only irradiation-induced defects in the 11 B 4 C sample, which may be annihilated during the annealing.…”

“…The residual damage of thermal conductivity of the irradiated 10 B 4 C sample could be attributed to the contribution of the substitutional defects, whereas the recovered proportion owes to the contribution of Frenkel defect pairs. On the basis of the thermal conductivity data of the irradiated 10 B 4 C samples before and after annealing [6], the proportion of the contribution of Frenkel defect pairs to that of the substitutional defects can be evaluated.…”

Fabrication and characterization of B4C-based ceramic composites with different mass fractions of hexagonal boron nitride

“…Boron carbide (B 4 C) ceramic has been widely used in various engineering fields, such as light-weight armor, high-temperature thermoelectric conversion elements, sliding bearings, seal rings, nozzles, and wear parts [1][2][3], due to its excellent properties of high hardness, high strength, low density, good high-temperature stability, high neutron absorption cross section and so on [4][5][6][7][8][9][10].…”