THE STUDY OF INTERNAL FRICTION OF ALUMINIUM BY THE METHOD OF DYNAMIC MECHANICAL ANALYSIS
Background. The construction materials, as a rule, are operated in alternating fields of various kinds and, therefore, change their properties continuously. Various methods are applied for investigation of micro processes in such materials. The DMA (dynamic mechanical analysis) method has proved to be very informative and productive among them. Materials and methods. By the method of dynamic mechanical analysis the authors investigated the influence of plastic deformation and temperature on the internal friction of aluminium. To determine the loss tangent (a measure of internal friction) the researchers used the device DMA/SDTA861e produced by METTLER TOLEDO. This device allows setting different modes of measurements, including temperature programs with dynamic and isothermal sections, single-frequency and multi-point measurements and scanning by load, amplitude and frequency. In this work the authors used the 3-point bending mode. Results. The article shows the dependence of the internal friction on the degree of plastic deformation for the samples of aluminum of technical purity. The study also contains information on the dependence of internal friction of the deformed aluminum aging time at different temperatures. Conclusions. Оn the graph of dependence of internal friction on the degree of plastic deformation the authors identified three areas that can be associated with structural changes in the process of hardening.