Thermally activated processes of fatigue crack growth in steels

Abstract

Fatigue crack growth rates in steels at high and low temperatures have been investigated using Paris curves. The fatigue crack growth rates at high temperatures are quite different from those at low temperatures. Arrhenius plots between fatigue crack growth rate (da/dN) and test temperatures at constant stress intensity factor range (ΔK_I) indicate a difference of the rate-controlling process for fatigue crack growth with temperature. Slip deformation at the crack tip governs fatigue crack growth at high temperatures, while hydrogen diffusion is associated with crack growth at low temperatures.

Keywords:

• fatigue crack growth
• dislocations
• thermally activated process
• steels

Funding

Part of this work was supported by JSPS KAKENHI [grant number 24686079], [grant number 22246090].