A MICROSTRUCTURE-BASED FATIGUE CRACK INITIATION MODEL FOR STRUCTURAL ALLOYS

摘要

The development of a microstructure-based fatigue crack initiation model that includes explicit crack size and microstructure-scale parameters is presented in this paper. In particular, Tanaka and Mura's model [1, 2] for crack initiation at slipbands has been extended to include crack size and relevant microstructural parameters in the response equations. The microstructure-based model is applied to predicting the crack size at initiation, small crack behavior, and notch fatigue in Ti-6Al-4V. The calculated results are compared against experimental data from the literature to assess the range of predictability and accuracy of the fatigue crack initiation model.