Peculiarities of changes of some physicomechanical characteristics of monoisotopes 10B, 11B and natural β-boron

Real structure and some physicomechanical characteristics of the samples of natural beta-rhombohedral boron B as well as of its 10B and 11B monoisotopes have been studied. It was shown that the influence of 10B and 11B isotopes on physicomechanical properties of boron had a different character. In particular, the samples enriched with 11B had high values of microhardness, shear modulus (SM) and elastic limit if compared to those of boron, while the samples enriched with 10B monoisotopes were characterized with high values of thermal expansion coefficient (TEC) and thermal conductivity; lattice parameters a and c increased by the sequence: 11B, B, 10B. It was established that TEC, thermal conductivity, microhardness, SM and shear elastic limit increased in all samples at annealing for 5 h at 1500 °C regardless of isotope content.