MICROSCOPIC AND MACROSCOPIC GROWTH RATES OF FATIGUE CRACKS IN STEELS AND ALLOYS UNDER THE INFLUENCE OF CRACK CLOSURE

摘要

On the basis of the experimental data, we show that the difference between the macroscopic and microscopic fatigue crack growth rates in the second section at the kinetic diagram of fatigue fracture is caused by the effect of crack closure within the limits of its existence. We establish the relationships between the macroscopic and microscopic fatigue crack growth rates and the structure of the material in the second section at the diagram for various values of the load ratio with regard for the effect of crack closure and propose a procedure at examination at the fracture processes in structural materials based on the analysis at microscopic and macroscopic fatigue crack growth rates.