REGULARITIES OF INFLUENCE OF CHEMICAL COMPOSITION ON MORPHOLOGYAND TYPE OF CARBIDES IN NICKEL-BASED SUPERALLOY

Abstract

Purpose. It consists in optimizing the chemical composition and morphology of carbides of the welded nickel-based superalloy by changing the chemical composition, which allows to increase the performance properties of body parts by improving the shape and size of the carbide component.
 Methods of  research Process modeling was performed by CALPHAD method. The initial data were the chemical compositions of model alloys with different concentrations of carbide-forming elements. The result of the calculation was the chemical compositions of carbides released in the respective systems. The experimental values were processed by the method of least squares to obtain correlation dependences of the "parameter-property" type and to establish mathematical equations of regression models that optimally describe these dependences.
 Results. Regularities of influence of chemical composition of metal on morphology and type of carbides are established. It is shown that depending on the introduced chemical elements in the system, the types of carbides and their chemical composition can change, which leads to a reduction of crack formation processes in the material. It is shown that the change in the composition of the material affects the shape, size and composition of the primary carbides.
 Scientific novelty. The established dependences of the multicomponent system Ni-22,5Cr-19Co-1,9Al-3,7Ti-2W-1,4Ta-1Nb-0,15C allow to determine the chemical composition of carbides by the chemical composition of the alloy. This makes it possible to change the types of carbides, their composition and morphology, thereby improving the mechanical properties of the material, first of all the fatigue and heat-resistant characteristics.
 Practical value. An effective solution for establishing the structural-phase state of nickel-based superalloys by optimizing their chemical composition, which allowed to improve the performance properties of the material. The established dependences can be used in optimizing the composition of industrial nickel-based superalloys and in the development of new compositions.