Features of the Mechanical Properties of Basalt Fibers
The results of the tensile tests of continuous basalt fiber (CBF) obtained in an experimental furnace are presented. A possibility of significant linear interpretation of the scale dependence of the mechanical characteristics on the fiber diameter is demonstrated within a diameter range of 7.2 - 21.6 μm: the correlation coefficients are, respectively, for the tensile strength r(σ t, d) = (-0.70), for the ultimate strain r(ε ul, d) = (-0.48), for the elastic modulus r( E, d) = (-0.44). The differences observed in the scale dependences are attributed to the special features of radial anisotropy of the fiber structure and to the different impact of defects on the mechanical characteristics depending on their location in the radial direction. Those factors also affect the correlation between the mechanical properties of CBF: correlation between the yield strength and ultimate strain is 0.88, between the tensile strength and modulus of elasticity is +0.35 (a significant deviation), while correlation between the modulus of elasticity and the ultimate strain are virtually absent r( E, ε ul) = -0.02. Strain diagram of studied CBF, unlike glass and carbon fibers, are characterized with broken lines, which is the inflection point (0.4 - 0.6)σ t. The relationships thus considered provide optimization of the process of high-strength CBF production.