CORROSION-MECHANICAL FATIGUE: THE PROBLEMS OF FORECASTING. PART 3. MECHANISMS OF CORROSION-MECHANICAL FATIGUE

Abstract

Corrosion is one of the main electrochemical processes that damage metal materials. The combination of cyclic stresses and a corrosive environment causes wear-fatigue damage, called corrosion-mechanical fatigue. The paper investigates the problem of predicting this type of corrosion-fatigue damage, which occurs in almost all branches of technology, especially in the chemical, oil, metallurgical industries, transport. The work consists of several parts. In the first part a technique for estimating the fatigue limit in a given corrosive environment (direct effect) is developed. The second part analyzes the reverse effect, i.e. the effect of acting stresses on the corrosion rate of metals and alloys, and proposes a method for predicting corrosion-erosion damage with the reverse effect based on the energy criterion. The third part discusses the mechanisms of corrosion-mechanical fatigue with direct and reverse effects taking into account the interacting phenomena of adsorption, hydrogen and corrosion fatigue itself. The concept of diffuse effect of multiple shear, oxidation, transfer is introduced as a complex type of damage in corrosion-mechanical fatigue.