Ranking of structural strength characteristics in the tasks of ensuring the durability and reliability of alloys

Abstract

The structure and properties of structural strength (CP) of wrought and cast nickel-based alloys, wrought steels and titanium alloys have been investigated. The features of degradation of materials of blades and disks of a turbocompressor after operational and bench operating time are revealed. According to the results of ultrasonic micro-flaw detection and electron microscopy, regularities of metal damage (microcracks, fatigue grooves and structure decay) from the size and composition of the strengthening phases of the alloys have been established. The properties of the KP of martensitic steel of the HPC HPU disks for the variants of technological and operational heredity by the characteristic of the indentation diagram have been agreed. The criteria for the maintainability of the hub part of the turbine disks made of a wrought nickel-based alloy after bench and operational operating time are substantiated. The fact of restoration of the operability of the metal of the disks subjected to repair with the use of heat treatment in the “rest” mode is controlled by the restoration of the microhardness values to the initial state. The defining structural strength characteristics of materials have been established according to the deformation diagram in true coordinates: strain hardening, ultimate plasticity, pull-off strength, Ilyushin’s modulus of high-strength steels, as well as the relative narrowing of titanium and nickel alloys in technological states for predicting the fatigue resistance of alloys. Calculations and experiments substantiate the structure and technology of alloys according to the criteria of fatigue resistance, characteristics of the true deformation diagram, indentation and microhardness.