Fatigue life improvement in lean duplex stainless steel by peening treatments.

R. STRUBBIA; HEREÑÚ, SILVINA; GÓMEZ ROSAS, GILBERTO; FUSTER, VALERIA; CARLOS RUBIO GONZÁLEZ

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2019 vol. 50 p. 5614 - 5626

1073-5623

The present work studies the effects of shot peening (SP) and laser shock peening without coating (LSPwC) on the low cycle fatigue life of the lean duplex stainless steel LDX 2101. LSPwC with two pulse densities, 2500 pulse/cm2 and 5000 pulse/cm2, were considered. In order to analyze the changes induced by each peening treatment, roughness, residual stress, hardness, quantitative phase analysis, qualitative surface chemical composition and dislocation microstructure were evaluated. This paper shows that SP and LSPwC induce in the surface; beneficial compressive residual stresses, increase of hardness and roughness and in the austenite phase a pronounced work hardening. The strong barrier of this hardened austenite phase to microcrack growth can explain the improvement in the fatigue life of LDX 2101 with peening treatments. Moreover, the highest fatigue life is achieved for the LSPwC treated material with 5000 pulse/cm2 due to the presence of deformation twins in the autenitic phase