Investigation of the change in technological properties of refractory metals after diffusion saturation

Abstract

The recommended ways of improving the technological and physico-mechanical properties of refractory metals (molybdenum and tungsten) after diffusion saturation with the elements of the same name are described. In order to increase significantly the performance characteristics and transition to stricter operating conditions for products made of refractory metals, it is necessary to improve the existing methods of processing metals and make significant changes in the development of new ones. Different directions of refractory metals processing, which involve diffusion saturation with elements of the same name, introduction of activating additives into the composition of the diffusion mixture, use of isothermal conditions during chemical-thermal treatment, and application of protective coating to improve technological and physical-mechanical properties, have been studied and analyzed. To evaluate changes in the mechanical properties of molybdenum and tungsten after diffusion saturation with the elements of the same name, appropriate tests were conducted. To study the changes in the technological and physical and mechanical properties of refractory metals after the process of diffusion saturation in active-aggressive environment, tests on static rupture and stretching, bending, impact bending and buckling were carried out. It has been established that it is possible to increase the technological characteristics and ensure the use of refractory metals in harsher operating conditions by introducing molybdenum and tungsten powders of the same name and activating additive (sodium fluoride) into the charge to obtain protective coating. Comparison of the magnitude of the temporary resistances values for of untreated samples breaks of refractory metals and samples that have undergone the appropriate heat treatment showed significant decrease in these indicators after diffusion saturation with the same elements (molybdenation and tungstenization). Based on the analysis of literature data and conducted research, a set of measures aimed at the improvement of technological and physico-mechanical properties of refractory metals (molybdenum and tungsten) after diffusion saturation with the same elements in powder medium is proposed.