Creep life and damage prediction in metals using an entropy generation-based model

Structural design requires reliable life evaluation. This study employs an approach based on the second law of thermodynamics and entropy generation to assess damage and predict the lifespan of metallic workpieces under uniaxial creep loading. The Norton method was used to calculate initial creep strain rates, followed by determining entropy generation rates and cumulative entropy to quantify damage. The results aligned well with experimental data, demonstrating that entropy generation at the end of the secondary creep stage is stress- and temperature-independent and can be considered a material characteristic. The entropy growth rate increased significantly upon entering the tertiary creep region, mirroring the creep strain rate trend. Stress and temperature influenced entropy generation and damage, with higher stress or temperature accelerating damage propagation. Normalized entropy diagrams were developed and matched with normalized lifetimes across various stress and temperature conditions, revealing material-specific, stress- and temperature-independent correlations. These findings highlight the applicability of entropy-based models for reliable creep life prediction in metals.