Rupture strength and fracture criteria of alloy �I698VD in a complex stress state

Abstract

1. In a plane stress state, the time to rupture of alloy EI698VD is described by Eq. (1). Here, an increase in the compressive component σ3 reduces the activation energy of the fracture process. This is confirmed by the results of metallographic study of fractured specimens. 2. Statistical evaluation of the results from analysis of test data using Eqs. (4) and (6)–(8) shows that only criterion (4) adequately describes the rupture strength of the alloy in a plane stress state. 3. The parameter χ depends on the activation parameters of the fracture process. In this case, when the fracture of a material in uniaxial tension and a complex stress state is governed by the same set of mechanisms, the parameter χ is a constant. If these mechanisms are different, then χ changes in relation to the temperature and time to rupture. In this case, it is necessary to use the weighted mean value of χ, which is found from Eq. (10).