INFLUENCE OF TEMPERATURE-VELOCITY DEFORMATION PARAMETERS ON STRUCTURES OF THE HEAT-RESISTANT NICKEL ALLOY

The paper aims at predicting structures of granular heat-resistant nickel alloys after hot deformation, which is significantly influenced by temperature-velocity deformation conditions. The developed method predicts the material’s structure based on stresses and temperatures arising in it during isothermal stamping. To form a required structure in granulated heat-resistant nickel alloys (HRNA), it is rational to use the conditions of close-to-isothermal or isothermal deformation. The temperature-velocity deformation conditions, which are chosen taking into account the chemical composition of the alloy and the required degree of deformation, have a significant effect on grain sizes. To assess the material structure, a relation was determined. This dependence can be obtained by experimental studies of the samples from the HRNA material, by conducting a sludge test with various degrees of deformation and by measuring the size of the γ' phase after the test. To determine the degree of influence of the deformation rate and deformation temperature on the change in the structure, microstructure studies of samples were carried out after sludge testing of HRNA with the determination of the size of the γ' phase. The microstructure was studied with a magnification of 10,000 times. We analyzed the results of studying deformability and microstructure of the HRNA alloy. According to these results, it was found that with an increase in the deformation temperature, the γ' phase both inside and at the grain boundary at all deformation rates was greater. It should be noted that low deformation rates at temperatures above 1100 ° C lead to a significant increase in the size of the γ' phase. Also there is a slight influence of the deformation temperature starting from 1100 ° C at velocities above 0.017 s-1.