MICROCRACKS ANALYSIS IN HIGH-STRENGTH BAINITIC STEEL DURING LOW-CYCLE FATIGUE

M.C. MARINELLI; M. BALBI

San Carlos de Bariloche

Congreso; 18º Congreso Internacional de Metalurgia y Materiales; 2018

Comisión Nacional de Energía Atómica

The behavior of fatigue microcracks in a high strength bainitic steel is studied. A gradual monitoring of microcracks development during LCF for different plastic strain amplitudes was performed using optical and electron microscopy, including EBSD data analysis. It is highlighted that there are two modes of initiation of microcracks according to the plastic strain applied. For Δεp< 0.2 % the microcracks preferably initiate along slip systems {110} with high Schmid factor and low Taylor factor, while at Δεp> 0.2 % they mostly nucleate at high-angle block boundaries. At Δεp = 0.2 % microcracks can nucleate along slip systems or at high-angle block boundaries.