Formation of microstructures responsible for remarkable properties of the Ni- and Co-based superalloys

Abstract

This article, by the example of 3 superalloys, discusses the principles that should be followed in designing new multicomponent alloys. Experimentally, it was shown that these principles are as follows: 1. Chemical interaction between dissimilar atoms exist always, in all alloys and at any temperature of heating; 2. Alloys have a not previously known property of changing the sign of the chemical interaction at a change of the temperature, subsequently leading to a change in the type of microstructures; 3. A model of pairwise interaction is realized in multicomponent alloys, according to which the chemical interaction between dissimilar atoms (which exists within each of the diffusion couples of a multicomponent alloy), occurs similarly to the chemical interaction in a corresponding binary alloy. Using this approach, it has been found experimentally that the process of partitioning of a multicomponent alloy into diffusion couples takes place in the liquid solution. It has been found that the remarkable properties of alloys of the Hastelloy and Tribaloy types are manifested by the fact that the tendency to phase separation takes place in the majority of their diffusion couples. It is shown that the formation of multicomponent chemical compounds (Laves phases) under conditions where in alloys there is a tendency to phase separation is impossible.