Influence of alloying systems on the lattice parameters of nickel-based superalloys

Abstract

The work aims to establish the relationship between the chemical composition, mechanical properties and dimensional mismatch of crystal lattices of heat-resistant nickel alloys.The results of experimental and calculated data formed based on experimental and taken from open sources results are presented. The XRD method used Bragg-Brentano determined the phase composition, focusing on a RIGAKU MINIFLEX 600 diffractometer (CoKα-radiation). After heat treatment, strength characteristics were determined on cylindrical samples with a working part (diameter 5 mm, length 25 mm). Testing of the alloy for short-term strength was carried out on samples at a temperature of 20C on UME-10TM and GCM-20 tensile machines. Alloy tests for long-term strength were carried out on similar samples at a temperature of 1000C on AIMA-5-2 and ZTZ 3/3 machines by uniaxial stretching under a constant load based on 100 hours.It has been established that with an increase in the value of the mismatch of crystal lattices, the strength of the alloys decreases due to significant internal stresses. It was revealed that for alloys of equiaxed and directional crystallisation, an extremum is observed at a value of 1.5 ... 1.6 K; this is associated with a decrease in the number of elements in the ϒ-solid solution.An essential problem is predicting the structure and properties of heat-resistant alloys without or with a minimum number of experiments. The results of comparative tests of the XDR method and calculated data are analysed.The obtained dependences can be used both for designing new heat-resistant alloys and for improving the compositions of industrial alloys.The value of this work lies in the fact that the dependences of the influence of alloying elements on the mechanical properties and the dimensional mismatch of crystal lattices were obtained, which made it possible to determine the properties without conducting experiments. It has been established that changes in the course of the relationship closely correlate with the processes taking place in the structure of alloys.