Small-angle neutron scattering investigation of plastically deformed stainless steel

The microstuctural evolution of plastically deformed steels has been studied by small-angle neutron scattering at ambient temperature in the range of momentum transfer q=(4pi/lambda) sin(Theta/2)= 0.01-5 nm(-1) where lambda is neutron wavelength and Q is the scattering angle. Samples of austenite stainless steels were pulled on a standard bench to cause a plastic deformation, S=0-60%, up to the fracture of the material. As a result of the deformation an increase of an order of magnitude was observed in the scatterred intensity I(q)similar to1/[1+(qR(C))(2)]((6-Ds)/2). The analysis of the I(q) distribution has shown the surface fractal nature of the observed nano-scale structures. The evolution of internal surface via intensive growth of pores ( size R(C)similar to20-40 nm) was found and a linear decrease of the surface fractal dimension 2.9greater than or equal toD(s)(S)greater than or equal to2.1 was observed. These findings can be used to design the fracture criteria for materials of industrial application.