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2006
Conference Paper
Titel
Study of martensitic transformation in fatigued stainless steel by neutron diffraction stress analysis
Abstract
The elastoplastic properties of a stainless steel AISI 321 with austenitic matrix and martensitic inclusions induced during cyclic tensile-compressive fatigue loading were studied using neutron diffraction. Nonlinear behaviour of the martensite elastic strain response in the plastic region was observed, while the austenite response remained practically linear. A clear trend of increasing elastic modulus with fatigue level was noted in the austenite of the low-cycle fatigued samples; the residual strains in austenite and the deviatoric components of residual microstresses in both phases were determined as a function of fatigue. The axial and transverse elastic constants of austenite and martensite in the high-cycle fatigued samples are distinctly different. In search of the reason of the last effect we have carried out on-line low-cycle plastic deformation transformation of one of the high-cycle fatigued samples.